Merge branch 'german/refactor-e12b-fake-engine-tests' into german/navara-refactor

scripts/qa-harness-baseline.json

@@ -4,6 +4,7 @@
     "fixedSleeps": 69,
     "loadingScreenReadiness": 0,
     "cesiumOnlyReads": 47,
-    "ownWaitHelpers": 16
+    "ownWaitHelpers": 16,
+    "testEngineLiterals": 2
   }
 }

scripts/qaHarness.test.mjs

@@ -2,17 +2,19 @@ import test from 'node:test';
 import assert from 'node:assert/strict';
 import {
   QA_HARNESS_METRICS,
+  engineLiteralLines,
   harnessGrowth,
   measureQaHarness,
   readBaseline,
   readQaSources,
+  readTestSources,
 } from './report-qa-harness.mjs';
 
 test('QA harness duplication does not grow past the baseline', () => {
   assert.deepEqual(
     harnessGrowth(measureQaHarness(), readBaseline().metrics),
     [],
-    'QA harness duplication grew; use scripts/qa-strict-harness.mjs helpers for browser launch, engine readiness and camera waits instead.',
+    'QA duplication grew; use the shared browser harness and src/globe/testing/fakeEngine.js for test engines.',
   );
 });
 
@@ -43,6 +45,83 @@ test('QA sources include the harness and exclude tests and other reports', () =>
   assert.ok(!names.includes('scripts/report-qa-harness.mjs'));
 });
 
+test('test sources include nested tests and exclude runtime files', () => {
+  const names = readTestSources().map(({ file }) => file);
+  assert.ok(names.includes('src/globe/testing/fakeEngine.test.mjs'));
+  assert.ok(names.includes('scripts/qaHarness.test.mjs'));
+  assert.ok(names.every((name) => name.endsWith('.test.mjs')));
+});
+
+test('engine literals include assignments, inline options and factory returns', () => {
+  for (const source of [
+    'const engine = {};',
+    'let engine; engine = { camera: {} };',
+    'scene.engine = { host: {} };',
+    "scene['engine'] = {};",
+    'init({ engine: {} });',
+    'const state = { _engine: {} };',
+    'const engineB = {}, trafficEngine = {};',
+    "function createEngine() { return { kind: 'cesium' }; }",
+    'const engine = () => ({ camera: {} });',
+    'const fakeEngine = () => { return { host: {} }; };',
+    'const factory = { createEngine() { return { render: {} }; } };',
+    'inspect({ host: { size() {} }, camera: {} });',
+    "const navara = { kind: 'navara', render: {} };",
+  ])
+    assert.ok(engineLiteralLines(source).length > 0, source);
+  assert.deepEqual(
+    engineLiteralLines('const engine = {};\ninit({ engine: {} });'),
+    [1, 2],
+  );
+});
+
+test('engine literal counting ignores source text, options and harness observations', () => {
+  for (const source of [
+    '// const engine = {};',
+    "const source = 'const engine = {};';",
+    'const source = `init({ engine: {} });`;',
+    'const engine = createFakeEngine();',
+    'init({ engine: createFakeEngine() });',
+    'const options = { engineOptions: {} };',
+    'const engineOptions = { canvas: {}, width: 800 };',
+    "const headers = { host: 'localhost' };",
+    'const overlay = { host: { setEntries() {} } };',
+    'result[engine] = { camera: {} };',
+    'function observedEngine() { return { engine, camera }; }',
+    'function observedEngine() { return { snapshots: [] }; }',
+    'function observedEngine() { return records.map(() => ({ camera: {} })); }',
+  ])
+    assert.deepEqual(engineLiteralLines(source), [], source);
+});
+
+test('engine literal metric counts test files once and rejects baseline growth', () => {
+  const metric = QA_HARNESS_METRICS.find(
+    ({ id }) => id === 'testEngineLiterals',
+  );
+  const measured = metric.measure([
+    {
+      file: 'src/one.test.mjs',
+      text: 'const engine = {}; init({ engine: {} });',
+    },
+    {
+      file: 'scripts/two.test.mjs',
+      text: 'const engine = () => ({ host: {} });',
+    },
+    { file: 'src/three.test.mjs', text: 'const engine = createFakeEngine();' },
+    { file: 'src/runtime.js', text: 'const engine = {};' },
+  ]);
+  assert.equal(measured, 2);
+  const baseline = Object.fromEntries(
+    QA_HARNESS_METRICS.map(({ id }) => [id, 0]),
+  );
+  assert.deepEqual(
+    harnessGrowth({ ...baseline, testEngineLiterals: measured }, baseline).map(
+      ({ id }) => id,
+    ),
+    ['testEngineLiterals'],
+  );
+});
+
 test('metrics count scripts once and distinguish helpers from their callers', () => {
   const measure = (id, ...sources) =>
     QA_HARNESS_METRICS.find((metric) => metric.id === id).measure(

scripts/report-qa-harness.mjs

@@ -1,7 +1,7 @@
 #!/usr/bin/env node
 /**
- * Browser QA still doing work owned by scripts/qa-strict-harness.mjs.
+ * Browser QA and tests still duplicating the shared harness or fake engine.
- * Each metric counts scripts, so repeated uses in one script count once.
+ * Each metric counts files, so repeated uses in one file count once.
  *
  *   node scripts/report-qa-harness.mjs
  *   node scripts/report-qa-harness.mjs --json
@@ -10,6 +10,7 @@
 import fs from 'node:fs';
 import path from 'node:path';
 import { fileURLToPath, pathToFileURL } from 'node:url';
+import { parsers } from 'prettier/plugins/babel.mjs';
 
 const ROOT = fileURLToPath(new URL('..', import.meta.url));
 export const BASELINE_PATH = path.join(
@@ -18,6 +19,80 @@ export const BASELINE_PATH = path.join(
   'qa-harness-baseline.json',
 );
 
+/** Engine assignments, inline options and engine factory returns, not strings or comments. */
+export function engineLiteralLines(text) {
+  const lines = [];
+  const engineName = (name) =>
+    !/Options$/.test(name ?? '') &&
+    /^(?:_?engine(?:[A-Z0-9]\w*)?|\w+Engine(?:[A-Z0-9]\w*)?)$/.test(name ?? '');
+  function walk(node, parent, factory) {
+    if (!node || typeof node !== 'object') return;
+    if (/Function|ObjectMethod/.test(node.type))
+      factory = node.id?.name ?? parent?.id?.name ?? node.key?.name;
+    if (node.type === 'ObjectExpression') {
+      const name =
+        parent?.type === 'VariableDeclarator'
+          ? parent.id?.name
+          : parent?.type === 'AssignmentExpression'
+            ? parent.left?.computed
+              ? parent.left.property?.value
+              : (parent.left?.property?.name ?? parent.left?.name)
+            : parent?.type === 'ObjectProperty'
+              ? (parent.key?.name ?? parent.key?.value)
+              : null;
+      const keys = node.properties.map((property) => property.key?.name);
+      const host = node.properties.find(
+        (property) => property.key?.name === 'host',
+      )?.value;
+      const globeHost =
+        host?.type === 'ObjectExpression' &&
+        host.properties.some((property) =>
+          ['canvas', 'container', 'size'].includes(property.key?.name),
+        );
+      const adapterKind = node.properties.some(
+        (property) =>
+          property.key?.name === 'kind' &&
+          ['cesium', 'navara'].includes(property.value?.value),
+      );
+      const returned =
+        parent?.type === 'ReturnStatement' ||
+        parent?.type === 'ArrowFunctionExpression';
+      // A factory's { engine, ...observations } is a harness, not its engine.
+      if (
+        engineName(name) ||
+        globeHost ||
+        (adapterKind &&
+          keys.some((key) =>
+            ['camera', 'render', 'credits', 'maps'].includes(key),
+          )) ||
+        (returned &&
+          engineName(factory) &&
+          !keys.includes('engine') &&
+          keys.some((key) =>
+            [
+              'kind',
+              'host',
+              'camera',
+              'frames',
+              'render',
+              'credits',
+              'maps',
+            ].includes(key),
+          ))
+      )
+        lines.push(node.loc.start.line);
+    }
+    for (const [key, value] of Object.entries(node)) {
+      if (['loc', 'comments', 'tokens'].includes(key)) continue;
+      if (Array.isArray(value))
+        for (const child of value) walk(child, node, factory);
+      else if (value && typeof value === 'object') walk(value, node, factory);
+    }
+  }
+  walk(parsers.babel.parse(text));
+  return lines;
+}
+
 const readsCesiumState = (text) => {
   const names = [
     '__godsEyeView',
@@ -78,6 +153,15 @@ export const QA_HARNESS_METRICS = Object.freeze([
         ),
       ).length,
   },
+  {
+    id: 'testEngineLiterals',
+    label: 'Test files with their own engine literal',
+    measure: (files) =>
+      files.filter(
+        ({ file, text }) =>
+          file.endsWith('.test.mjs') && engineLiteralLines(text).length,
+      ).length,
+  },
 ]);
 
 /** QA scripts, including the shared harness itself, but excluding tests. */
@@ -92,10 +176,29 @@ export function readQaSources(root = ROOT) {
     }));
 }
 
+export function readTestSources(root = ROOT) {
+  return ['build', 'scripts', 'server', 'src'].flatMap((directory) => {
+    const base = path.join(root, directory);
+    if (!fs.existsSync(base)) return [];
+    return fs
+      .readdirSync(base, { recursive: true })
+      .sort()
+      .filter((name) => name.endsWith('.test.mjs'))
+      .map((name) => ({
+        file: `${directory}/${name.split(path.sep).join('/')}`,
+        text: fs.readFileSync(path.join(base, name), 'utf8'),
+      }));
+  });
+}
+
 export function measureQaHarness(root = ROOT) {
   const files = readQaSources(root);
+  const tests = readTestSources(root);
   return Object.fromEntries(
-    QA_HARNESS_METRICS.map(({ id, measure }) => [id, measure(files)]),
+    QA_HARNESS_METRICS.map(({ id, measure }) => [
+      id,
+      measure(id === 'testEngineLiterals' ? tests : files),
+    ]),
   );
 }
 

src/annotations/annotationSession.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import { test } from 'node:test';
 import assert from 'node:assert/strict';
 import { createAnnotationEngine } from './annotationEngine.js';
@@ -69,7 +70,7 @@ test('the marks survive a globe leaving and are drawn again on the next one', as
 
   log.length = 0;
   engine.attachRenderer({
-    engine: {},
+    engine: createFakeEngine(),
     renderer: recordingRenderer(log, 'next'),
   });
   assert.deepEqual(log, ['next add Capitol']);
@@ -88,8 +89,14 @@ test('detaching twice and attaching over an attached globe release each drawing
   });
   engine.detachRenderer();
   engine.detachRenderer();
-  engine.attachRenderer({ engine: {}, renderer: recordingRenderer(log, 'b') });
+  engine.attachRenderer({
-  engine.attachRenderer({ engine: {}, renderer: recordingRenderer(log, 'c') });
+    engine: createFakeEngine(),
+    renderer: recordingRenderer(log, 'b'),
+  });
+  engine.attachRenderer({
+    engine: createFakeEngine(),
+    renderer: recordingRenderer(log, 'c'),
+  });
   assert.deepEqual(log, ['a destroy', 'b destroy']);
   engine.destroy();
 });

src/annotations/drawToolBehaviour.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 // Behavioural tests for the draw tool: the module is driven against fake DOM
 // and viewer doubles and its OBSERVABLE effects are asserted — which lease it
 // holds, which viewer input actions it borrowed and gave back, what it leaves
@@ -975,7 +976,7 @@ test('a page without the Draw controls gets no draw tool', () => {
   try {
     let connected = false;
     const tool = initDrawTool({
-      engine: {},
+      engine: createFakeEngine(),
       annotations: fakeAnnotations(),
       connect: () => {
         connected = true;

src/annotations/hybridAnnotationRenderer.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import { installDomClasses } from '../testSupport/domClasses.mjs';
 import { test } from 'node:test';
 import assert from 'node:assert/strict';
@@ -127,10 +128,9 @@ function fakeViewer(lon, lat) {
       },
     };
   // The Cesium engine's credits over the viewer's credit display.
-  const engine = {
+  const engine = createFakeEngine();
-    credits: createCesiumCredits(viewer).credits,
+  engine.credits = createCesiumCredits(viewer).credits;
-    render: { request: () => scene.requestRender() },
+  engine.render.request = () => scene.requestRender();
-  };
   enginesOf.set(viewer, engine);
   return { dataSources, frames, viewer, engine };
 }

src/annotations/resolverHighTerrain.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import assert from 'node:assert/strict';
 import test from 'node:test';
 import * as geo from '../geo/index.js';
@@ -9,18 +10,11 @@ test('a depth pick on high terrain close to the camera is kept', () => {
   const camera = geo.cartesian3.fromDegrees(86.9, 27.9, 4030);
   const ground = geo.cartesian3.fromDegrees(86.9, 27.9, 4000);
   const seaLevel = geo.cartesian3.fromDegrees(86.9, 27.9, 0);
-  const engine = {
+  const engine = createFakeEngine({ width: 100, height: 100 });
-    host: { size: () => ({ width: 100, height: 100 }) },
+  engine.fake.setPose({ position: camera });
-    picker: {
+  engine.fake.script('pickPosition', () => geo.cartesian3.clone(ground));
-      pickPositionSupported: true,
+  engine.fake.script('pickGlobe', () => geo.cartesian3.clone(ground));
-      pickPosition: () => geo.cartesian3.clone(ground),
+  engine.fake.script('pickEllipsoid', () => geo.cartesian3.clone(seaLevel));
-      pickGlobe: () => geo.cartesian3.clone(ground),
-    },
-    camera: {
-      livePosition: camera,
-      pickEllipsoid: () => geo.cartesian3.clone(seaLevel),
-    },
-  };
   const picked = pickWorldFromScreen(engine, 0.5, 0.5);
   assert.ok(
     Math.abs(picked.height - 4000) < 1,
@@ -29,35 +23,35 @@ test('a depth pick on high terrain close to the camera is kept', () => {
 });
 
 test('a near-camera depth artifact falls back to terrain before sea level', () => {
-  const engine = {
+  const engine = createFakeEngine({ width: 100, height: 100 });
-    host: { size: () => ({ width: 100, height: 100 }) },
+  engine.fake.setPose({
-    picker: {
+    position: geo.cartesian3.fromDegrees(86.9, 27.9, 4030),
-      pickPositionSupported: true,
+  });
-      pickPosition: () => geo.cartesian3.fromDegrees(86.9, 27.9, 4029),
+  engine.fake.script('pickPosition', () =>
-      pickGlobe: () => geo.cartesian3.fromDegrees(86.9, 27.9, 4000),
+    geo.cartesian3.fromDegrees(86.9, 27.9, 4029),
-    },
+  );
-    camera: {
+  engine.fake.script('pickGlobe', () =>
-      livePosition: geo.cartesian3.fromDegrees(86.9, 27.9, 4030),
+    geo.cartesian3.fromDegrees(86.9, 27.9, 4000),
-      pickEllipsoid: () => geo.cartesian3.fromDegrees(86.9, 27.9, 0),
+  );
-    },
+  engine.fake.script('pickEllipsoid', () =>
-  };
+    geo.cartesian3.fromDegrees(86.9, 27.9, 0),
+  );
   assert.ok(Math.abs(pickWorldFromScreen(engine, 0.5, 0.5).height - 4000) < 1);
 });
 
 test('a far camera still treats a near-plane depth hit as a miss', () => {
   // 100 km up: a preview drawn at the near plane reads back 50 m away.
   const camera = geo.cartesian3.fromDegrees(86.9, 27.9, 100_000);
-  const engine = {
+  const engine = createFakeEngine({ width: 100, height: 100 });
-    host: { size: () => ({ width: 100, height: 100 }) },
+  engine.fake.setPose({ position: camera });
-    picker: {
+  engine.fake.script('pickPosition', () =>
-      pickPositionSupported: true,
+    geo.cartesian3.fromDegrees(86.9, 27.9, 99_950),
-      pickPosition: () => geo.cartesian3.fromDegrees(86.9, 27.9, 99_950),
+  );
-      pickGlobe: () => geo.cartesian3.fromDegrees(86.9, 27.9, 4000),
+  engine.fake.script('pickGlobe', () =>
-    },
+    geo.cartesian3.fromDegrees(86.9, 27.9, 4000),
-    camera: {
+  );
-      livePosition: camera,
+  engine.fake.script('pickEllipsoid', () =>
-      pickEllipsoid: () => geo.cartesian3.fromDegrees(86.9, 27.9, 0),
+    geo.cartesian3.fromDegrees(86.9, 27.9, 0),
-    },
+  );
-  };
   assert.ok(Math.abs(pickWorldFromScreen(engine, 0.5, 0.5).height - 4000) < 1);
 });

src/app/application.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import { spawnSync } from 'node:child_process';
@@ -111,7 +112,7 @@ test('startup shares one promise and teardown keeps data alive for controls', as
 
 test('later components receive the scene engine beside its viewer', async () => {
   const viewer = { name: 'viewer' };
-  const engine = { kind: 'cesium' };
+  const engine = createFakeEngine({ kind: 'cesium' });
   const seen = [];
   const receive =
     (phase) =>

src/app/controlsSceneFailure.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 // A candidate engine that fails after the shell attached to it (a later
 // part: data, Cockpit clouds) must leave the shell detached, so the working
 // engine attaches again.
@@ -29,7 +30,7 @@ test('a candidate failing in a later part leaves the shell ready for the working
   const cesium = {
     kind: 'cesium',
     viewer: null,
-    engine: { kind: 'cesium' },
+    engine: createFakeEngine({ kind: 'cesium' }),
     catalog,
   };
   await sceneHost.attach(cesium);
@@ -49,7 +50,7 @@ test('a candidate failing in a later part leaves the shell ready for the working
   const navara = {
     kind: 'navara',
     viewer: null,
-    engine: { kind: 'navara' },
+    engine: createFakeEngine({ kind: 'navara' }),
     catalog,
   };
   await assert.rejects(sceneHost.attach(navara), /layer attachment failed/);

src/app/embed.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import assert from 'node:assert/strict';
 import test from 'node:test';
 import {
@@ -12,15 +13,13 @@ import { createView } from '../view/index.js';
 
 const fakeEngine = () => {
   const flights = [];
-  return {
+  const engine = createFakeEngine();
-    flights,
+  engine.flights = flights;
-    camera: {
+  engine.camera.flyTo = (options) => {
-      flyTo(options) {
+    flights.push(options);
-        flights.push(options);
+    options.complete();
-        options.complete();
-      },
-    },
   };
+  return engine;
 };
 const fakeLayers = (enabled) => ({
   getAll: () =>

src/app/globeEngine.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import fs from 'node:fs';
@@ -23,7 +24,9 @@ test('the scene engine is built on the viewer and destroyed by the scene lifetim
     defer: (dispose) => cleanups.push(dispose),
     createEngine(target, options) {
       calls.push([target, options]);
-      return { kind: 'cesium', destroy: () => calls.push('destroy') };
+      const engine = createFakeEngine();
+      engine.destroy = () => calls.push('destroy');
+      return engine;
     },
   });
   assert.equal(engine.kind, 'cesium');

src/app/mainStartup.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import '../testSupport/registerDom.mjs';
 import test from 'node:test';
 import assert from 'node:assert/strict';
@@ -73,6 +74,8 @@ function boot(
       };
     },
     createStandaloneApplication: ({ engineKind }) => {
+      const engine = createFakeEngine({ kind: engineKind });
+      engine.camera.completeFlight = () => flushes.push('flight');
       const styleManager = {
         initialRestorePromise,
         shareLinkManager: { flush: () => flushes.push('share link') },
@@ -92,9 +95,7 @@ function boot(
         }),
         getComponents: () => ({
           scene: {
-            engine: {
+            engine: engine,
-              camera: { completeFlight: () => flushes.push('flight') },
-            },
           },
           controls: { styleManager },
         }),

src/app/navaraToolBackend.test.mjs

@@ -42,10 +42,8 @@ test('Navara draws the page session board and its switch takes only the drawing'
   const lifetime = new AbortController();
   const layerSession = { lifetime };
   const { views, meshes } = fakeViews();
-  const engine = {
+  const engine = createFakeEngine({ kind: 'navara' });
-    ...createFakeEngine({ kind: 'navara' }),
+  engine.extensions = { navara: views };
-    extensions: { navara: views },
-  };
   // As src/app/tools.js attaches the board on the backend's scene.
   const attach = () => {
     const cleanups = [];

src/celestialRingFocus.test.mjs

@@ -1,21 +1,12 @@
+import { createFakeEngine } from './globe/testing/fakeEngine.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import { CelestialRing } from './celestialRing.js';
 
 test('full globe focus uses the engine without a Cesium global', () => {
   let flight;
-  const engine = {
+  const engine = createFakeEngine({ canvas: { clientWidth: 1200, clientHeight: 800 }, fovy: Math.PI / 3 });
-    host: { canvas: { clientWidth: 1200, clientHeight: 800 } },
+  engine.camera.flyTo = (options) => { flight = options; };
-    render: { request() {} },
-    camera: {
-      pose: () => ({
-        cartographic: { longitude: 0, latitude: 0 },
-        heading: 0,
-        fovy: Math.PI / 3,
-      }),
-      flyTo: (options) => { flight = options; },
-    },
-  };
   const ring = Object.assign(Object.create(CelestialRing.prototype), {
     _engine: engine,
   });

src/data/bhoteKoshiEvent.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import assert from 'node:assert/strict';
 import { readFile } from 'node:fs/promises';
 import test from 'node:test';
@@ -3142,11 +3143,8 @@ test('Bhote Koshi republishes its evidence cards to the incoming engine overlay'
   globalThis.window = { setTimeout: () => 1, clearTimeout() {} };
   const first = eventViewer();
   const second = eventViewer();
-  const engineB = {
+  const engineB = createFakeEngine({ canvas: second.scene.canvas });
-    id: 'B',
+  engineB.id = 'B';
-    host: { canvas: second.scene.canvas },
-    camera: second.camera,
-  };
   const hosts = new Map();
   const hostFor = (engine) => {
     const key = engine ?? 'A';
@@ -3216,16 +3214,11 @@ async function navaraEvidenceCard({ sample, signal }) {
   installEventDom();
   globalThis.window = { setTimeout: () => 1, clearTimeout() {} };
   const entries = [];
-  const engine = {
+  const engine = createFakeEngine({ canvas: eventViewer().scene.canvas });
-    terrain: 3500,
+  engine.terrain = 3500;
-    host: { canvas: eventViewer().scene.canvas },
+  engine.fake.script('terrainHeight', () => engine.terrain);
-    surface: {
+  engine.fake.script('sampleTerrainMostDetailed', sample);
-      terrainHeight: () => engine.terrain,
+  engine.maps.terrainRevision = () => 1;
-      sampleTerrainMostDetailed: sample,
-    },
-    maps: { terrainRevision: () => 1 },
-    camera: { livePosition: Cesium.Cartesian3.fromDegrees(0, 0, 1e7) },
-  };
   const layer = buildEventLayer({
     eventLoader: async () => event,
     imageLoader: async (url) => ({ url }),
@@ -3330,11 +3323,9 @@ test('Navara evidence anchors without a terrain sample follow the terrain near t
     assert.ok(Math.abs(height() - pack) < 0.01, 'the pack elevation');
     card.position();
     assert.ok(Math.abs(height() - pack) < 0.01, 'a far camera keeps it');
-    engine.camera.livePosition = Cesium.Cartesian3.fromDegrees(
+    engine.fake.setPose({
-      first.lon,
+      position: Cesium.Cartesian3.fromDegrees(first.lon, first.lat, 6000),
-      first.lat,
+    });
-      6000,
-    );
     engine.terrain = 2000;
     assert.ok(card.position(), 'the first card is shown');
     assert.ok(

src/data/bhoteKoshiLocator.edgeCases.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 // Edge cases for bhote-koshi-locator: a boundary that resolves late, after its
 // request was cancelled, does not change the live scene; both engines show the
 // same area and the same target.
@@ -42,11 +43,8 @@ function locator(engine) {
       remove: (source) => shown.delete(source),
     },
   };
-  const navara = {
+  const navara = createFakeEngine({ kind: 'navara' });
-    kind: 'navara',
+  navara.render.request = (reason) => renders.push(reason);
-    render: { request: (reason) => renders.push(reason) },
-    credits: { add() {}, remove() {} },
-  };
   const layer = createBhoteKoshiLocatorLayer({
     boundaryResolver: (signal) => {
       const lookup = deferred();
@@ -176,11 +174,7 @@ test('edge:bhote-koshi-locator: an engine swap while the boundary resolves lands
   const enabling = layer.enable(viewer);
   layer.detachRenderer();
   layer.attachRenderer({
-    engine: {
+    engine: createFakeEngine({ kind: 'navara' }),
-      kind: 'navara',
-      render: { request() {} },
-      credits: { add() {}, remove() {} },
-    },
   });
   lookup.resolve({ ring: LIVE_RING });
   assert.equal(await enabling, true);

src/data/dataCredits.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import { test } from 'node:test';
 import assert from 'node:assert/strict';
 import {
@@ -94,10 +95,9 @@ test('OpenStreetMap has one generic data credit with separate tile and names dis
 // A Cesium engine's credits over a viewer double's credit display.
 async function cesiumCreditsEngine(viewer) {
   const { createCesiumCredits } = await import('../globe/cesium/credits.js');
-  return {
+  return Object.assign(createFakeEngine(), {
     credits: createCesiumCredits(viewer).credits,
-    render: { request() {} },
+  });
-  };
 }
 
 test('inline OSM attribution persists until its last display owner leaves', async (t) => {

src/data/lifecycleScene.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import { LayerLifecycle } from './lifecycle.js';
@@ -46,7 +47,7 @@ function catalog(...modules) {
   };
 }
 
-const engine = (name) => ({ kind: 'test', name });
+const engine = (name) => Object.assign(createFakeEngine({ kind: 'test' }), { name });
 const firstViewer = { name: 'first viewer' };
 const secondViewer = { name: 'second viewer' };
 
@@ -86,6 +87,7 @@ const detaches = (calls) => calls.filter((call) => call[0] === 'detach');
 const attaches = (calls) => calls.filter((call) => call[0] === 'attach');
 
 test('one failing detachRenderer leaves the others released and the manager unbound', async () => {
+  const second = engine('second');
   let failures = 1;
   const broken = sceneLayer('broken', {
     detach() {
@@ -122,16 +124,17 @@ test('one failing detachRenderer leaves the others released and the manager unbo
   // The next scene binds and both retained layers attach to it.
   await bindCatalog(
     manager,
-    engine('second'),
+    second,
     catalog(...modules),
   );
   assert.equal(manager.viewer, secondViewer);
-  assert.deepEqual(attaches(broken.calls).at(-1), ['attach', engine('second')]);
+  assert.deepEqual(attaches(broken.calls).at(-1), ['attach', second]);
-  assert.deepEqual(attaches(after.calls).at(-1), ['attach', engine('second')]);
+  assert.deepEqual(attaches(after.calls).at(-1), ['attach', second]);
   assert.equal(manager.isEnabled('broken'), true);
 });
 
 test('bindCatalog after a failed detach retries the release before attaching', async () => {
+  const second = engine('second');
   let failures = 1;
   const broken = sceneLayer('broken', {
     detach() {
@@ -146,13 +149,13 @@ test('bindCatalog after a failed detach retries the release before attaching', a
 
   await bindCatalog(
     manager,
-    engine('second'),
+    second,
     catalog(...modules),
   );
   assert.deepEqual(broken.calls.slice(-3), [
     ['detach', firstViewer],
     ['detach', firstViewer],
-    ['attach', engine('second')],
+    ['attach', second],
   ]);
   // The scene is settled: the next detach releases the second viewer once.
   await manager.detachScene();
@@ -419,6 +422,7 @@ test('an explicit refresh between scenes ends false when its caller aborts', asy
 });
 
 test('a layer enabled between scenes initializes on the next scene', async () => {
+  const second = engine('second');
   const late = sceneLayer('late');
   const present = sceneLayer('present');
   const { manager, modules } = await boundManager(present);
@@ -429,9 +433,9 @@ test('a layer enabled between scenes initializes on the next scene', async () =>
   const enabled = manager.setEnabled('late', true, { origin: 'user' });
   await tick();
   assert.deepEqual(late.calls, [], 'no init against a missing scene');
-  await bindCatalog(manager, engine('second'), catalog(...all));
+  await bindCatalog(manager, second, catalog(...all));
   assert.equal(await enabled, true);
-  assert.deepEqual(late.calls.slice(0, 2), ['init', ['attach', engine('second')]]);
+  assert.deepEqual(late.calls.slice(0, 2), ['init', ['attach', second]]);
 });
 
 test('a detach does not deadlock on an enable parked for the next scene', async () => {

src/data/militaryAwareness.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import { readFileSync } from 'node:fs';
 import { readLayerSource } from '../testSupport/readLayerSource.mjs';
 import { test } from 'node:test';
@@ -77,14 +78,14 @@ const {
 } = militaryAwarenessLayer;
 const viewerEngines = new WeakMap();
 const viewerEngine = (viewer) => {
-  if (!viewerEngines.has(viewer)) viewerEngines.set(viewer, {
+  if (!viewerEngines.has(viewer)) {
-    kind: 'cesium', viewer,
+    const engine = createFakeEngine();
-    render: {
+    engine.viewer = viewer;
-      request: () => viewer.scene.requestRender?.(),
+    engine.render.request = () => viewer.scene.requestRender?.();
-      setContinuous: (enabled) => { viewer.scene.requestRenderMode = !enabled; },
+    engine.render.setContinuous = (enabled) => { viewer.scene.requestRenderMode = !enabled; };
-      isContinuous: () => viewer.scene.requestRenderMode === false,
+    engine.render.isContinuous = () => viewer.scene.requestRenderMode === false;
-    },
+    viewerEngines.set(viewer, engine);
-  });
+  }
   return viewerEngines.get(viewer);
 };
 

src/data/osmOverlays.test.mjs

@@ -12,11 +12,8 @@ import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 /** A layer on the fake engine, whose imagery drapes where `surface()` says. */
 function setup(overlay = OSM_OVERLAYS[0]) {
   let surface = 'globe';
-  const fake = createFakeEngine({ kind: 'cesium' });
+  const engine = createFakeEngine({ kind: 'cesium' });
-  const engine = {
+  engine.imagery.surface = () => surface;
-    ...fake,
-    imagery: { ...fake.imagery, surface: () => surface },
-  };
   const layer = createOsmOverlayLayer(overlay);
   layer.init(null, { engine });
   return {
@@ -120,15 +117,15 @@ test('destroy and a renderer detach remove the owned imagery', () => {
 
 test('on Navara an overlay drapes through engine.maps and follows the globe', () => {
   const added = [];
-  const engineWith = () => ({
+  const engineWith = () => {
-    maps: {
+    const engine = createFakeEngine({ kind: 'navara' });
-      addOverlay(options) {
+    engine.maps.addOverlay = (options) => {
-        const entry = { options, removed: false };
+      const entry = { options, removed: false };
-        added.push(entry);
+      added.push(entry);
-        return () => (entry.removed = true);
+      return () => (entry.removed = true);
-      },
+    };
-    },
+    return engine;
-  });
+  };
   const [seaMarks] = createOsmOverlayLayers();
   seaMarks.init(null, { engine: engineWith() });
   assert.equal(added.length, 0, 'nothing until enabled');

src/data/pickedContext.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import assert from 'node:assert/strict';
 import test from 'node:test';
 
@@ -11,7 +12,7 @@ globalThis.CustomEvent ||= class CustomEvent {
 globalThis.dispatchEvent ||= () => true;
 
 const { registerEntityContext } = await import('./contextStore.js');
-const engine = {};
+const engine = createFakeEngine();
 const { pickRegistryFor } = await import('./pickRegistry.js');
 const { registerPickOwner, unregisterPickOwner, findPickOwner } = pickRegistryFor(engine);
 const { resolvePickedContext, pickedKindForLayer } = await import('./pickedContext.js');

src/data/radio.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import assert from 'node:assert/strict';
 import test from 'node:test';
 import {
@@ -1638,7 +1639,8 @@ test('Radio recovery preserves closer altitude and caps extreme full-globe zoom'
 
 test('Radio camera navigation yields to every live tracked-entity owner', () => {
   let following = null;
-  const engine = { camera: { following: () => following } };
+  const engine = createFakeEngine();
+  engine.camera.following = () => following;
   assert.equal(radioCameraNavigationAllowed(engine), true);
   for (const gevTrackedId of ['flights:abc123', 'military:def456']) {
     const trackedEntity = { gevTrackedId };

src/data/telegeographySubmarineCables.test.mjs

@@ -221,9 +221,11 @@ test('cable paths drape on exactly the active surface on every stack', () => {
 
   // Boot fires no stack event; the first drape comes from the engine:
   // photoreal tiles shown ⇔ the globe hidden.
-  const engine = (photoreal) => ({
+  const engine = (photoreal) => {
-    maps: { photorealActive: () => photoreal },
+    const globe = createFakeEngine();
-  });
+    globe.maps.photorealActive = () => photoreal;
+    return globe;
+  };
   assert.equal(cableDrapeForEngine(engine(true)), 'tiles');
   assert.equal(cableDrapeForEngine(engine(false)), 'terrain');
   assert.equal(cableDrapeForEngine(null), 'both');

src/data/trackedModelRegime.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import { readLayerSource } from '../testSupport/readLayerSource.mjs';
 // src/data/trackedModelRegime.test.mjs
 //
@@ -172,16 +173,12 @@ function viewerAtHeight(height, { tilesLoaded = true, sampleHeight = () => undef
     trackedEntity: undefined,
     entities: { remove() {} },
   };
-  viewer.engine = {
+  viewer.engine = createFakeEngine();
-    isDestroyed: () => false,
+  viewer.engine.fake.script('tilesLoaded', () => viewer.tileset.tilesLoaded === true);
-    surface: {
+  viewer.engine.fake.script('sampleHeightDetailed', (place, { exclude } = {}) => {
-      tilesLoaded: () => viewer.tileset.tilesLoaded === true,
+    const h = viewer.scene.sampleHeight(place, exclude);
-      sampleHeightDetailed(place, { exclude } = {}) {
+    return Number.isFinite(h) ? { height: h, source: 'tiles' } : undefined;
-        const h = viewer.scene.sampleHeight(place, exclude);
+  });
-        return Number.isFinite(h) ? { height: h, source: 'tiles' } : undefined;
-      },
-    },
-  };
   return viewer;
 }
 

src/data/trackedReadout.visualAnchor.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import { createTrackedReadout } from './trackedReadout.js';
@@ -19,18 +20,8 @@ test('followed aircraft card anchors to the model the person sees (gevVisualPosi
       position: () => native.gevDisplayPosition(),
     },
   };
-  const listeners = [];
+  const engine = createFakeEngine();
-  const engine = {
+  engine.camera.following = () => handle;
-    camera: {
-      following: () => handle,
-      followChanged: {
-        addEventListener: (f) => {
-          listeners.push(f);
-          return () => {};
-        },
-      },
-    },
-  };
   let entries = null;
   const overlay = {
     setEntries(_id, e) {

src/data/trafficTiming.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import assert from 'node:assert/strict';
 import { readLayerSource } from '../testSupport/readLayerSource.mjs';
 import { mkdtempSync, rmSync } from 'node:fs';
@@ -214,68 +215,38 @@ test('traffic timing pairs real ordering to the scheduling change and guards re-
     const changed = eventChannel();
     let longitude = -97.74;
     const cartographic = { latitude: Math.PI / 6, longitude: 0, height: 5000 };
-    const camera = {
+    // A zero-size canvas has no reticle footprint; the view rectangle bounds the fetch.
-      moveEnd,
+    const engine = createFakeEngine({
-      changed,
+      width: 0,
-      percentageChanged: 0.5,
+      height: 0,
-      livePosition: { x: 0, y: 0, z: 0 },
+      canvas: { clientWidth: 0, clientHeight: 0, width: 0, height: 0 },
-      pose: () => ({ cartographic: { ...cartographic }, heading: 0, pitch: -Math.PI / 2 }),
+    });
-      viewRectangle() {
+    engine.camera.moveEnd = moveEnd;
-        const west = longitude * Math.PI / 180;
+    engine.camera.changed = changed;
-        return {
+    engine.camera.pose = () => ({ cartographic: { ...cartographic }, heading: 0, pitch: -Math.PI / 2 });
-          south: 30 * Math.PI / 180,
+    engine.fake.script('viewRectangle', () => {
-          west,
+      const west = longitude * Math.PI / 180;
-          north: 30.02 * Math.PI / 180,
+      return {
-          east: west + 0.02 * Math.PI / 180,
+        south: 30 * Math.PI / 180,
-        };
+        west,
-      },
+        north: 30.02 * Math.PI / 180,
-      pickEllipsoid: () => undefined,
+        east: west + 0.02 * Math.PI / 180,
-    };
+      };
+    });
+    engine.fake.script('pickEllipsoid', undefined);
+    engine.fake.script('worldToWindow', undefined);
+    engine.frames.preUpdate = preUpdate;
+    engine.frames.preRender = preRender;
+    engine.frames.postRender = postRender;
+    engine.projector.viewProjection = (result = new Array(16).fill(0)) => result;
+    engine.projector.horizonVisible = () => true;
+    engine.picker.pickPositionSupported = false;
+    engine.surface.supported = false;
     const setLongitude = (next) => {
       longitude = next;
       cartographic.longitude = next * Math.PI / 180;
     };
     setLongitude(longitude);
-    const noSet = () => ({
-      set() {},
-      setCount() {},
-      commit() {},
-      replace() {},
-      show() {},
-      destroy() {},
-    });
-    // An engine on a zero-size canvas: no pick ray (no reticle footprint),
-    // so the fetch is bounded by the view rectangle.
-    const engine = {
-      kind: 'cesium',
-      host: {
-        canvas: { clientWidth: 0, clientHeight: 0, width: 0, height: 0 },
-        size: () => ({ width: 0, height: 0 }),
-      },
-      camera,
-      frames: { preUpdate, preRender, postRender },
-      projector: {
-        worldToWindow: () => undefined,
-        viewProjection: (result = new Array(16).fill(0)) => result,
-        horizonVisible: () => true,
-      },
-      picker: { pickPositionSupported: false },
-      surface: {
-        supported: false,
-        terrainHeight: () => 0,
-        sampleHeight: () => undefined,
-        tilesLoaded: () => true,
-      },
-      maps: {
-        photorealActive: () => false,
-        current: () => ({ baseImagery: null, photoreal: null }),
-      },
-      render: { request() {} },
-      credits: { addStatic: () => () => {} },
-      movers: { createSet: noSet },
-      ground: { createSet: noSet },
-      destroy() {},
-    };
 
     performance.clearMarks();
     performance.clearMeasures();

src/globe/navara/meshes.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../testing/fakeEngine.js';
 import assert from 'node:assert/strict';
 import test from 'node:test';
 import {
@@ -42,16 +43,13 @@ function harness() {
     },
   };
   const pickers = new Set();
-  const engine = {
+  const engine = createFakeEngine({ kind: 'navara' });
-    render: { request: () => requests++ },
+  engine.render.request = () => requests++;
-    camera: { livePosition: { x: 0, y: 0, z: 0 }, pickRay: () => null },
+  engine.camera.pickRay = () => null;
-    picker: {
+  engine.fake.script('pickPosition', undefined);
-      pickPosition: () => undefined,
+  engine.picker.registerMeshPicker = (pick) => {
-      registerMeshPicker(pick) {
+    pickers.add(pick);
-        pickers.add(pick);
+    return () => pickers.delete(pick);
-        return () => pickers.delete(pick);
-      },
-    },
   };
   const port = createNavaraMeshes(view, {
     overlay,

src/globe/navara/sceneDepth.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../testing/fakeEngine.js';
 import assert from 'node:assert/strict';
 import test from 'node:test';
 import {
@@ -140,7 +141,7 @@ test('pack meshes draw in the overlay and test the scene depth', () => {
     camera: {},
     picker: { registerMeshPicker: () => () => {} },
   });
-  const engine = { meshes: port.meshes, render: { request() {} } };
+  const engine = Object.assign(createFakeEngine(), { meshes: port.meshes });
   createPackRenderer(engine).image(
     { id: 'p', placement: { bounds: [0, 0, 0.01, 0.01], height: 300 } },
     {},

src/layers/aircraft/sceneBinding.test.mjs

@@ -1,8 +1,8 @@
+import { createFakeEngine } from '../../globe/testing/fakeEngine.js';
 import assert from 'node:assert/strict';
 import test from 'node:test';
 import { createAircraftSceneBinding } from './sceneBinding.js';
 import { LayerBindings } from '../../ui/layerBindings.js';
-import { createEngineEvent } from '../../globe/contract.js';
 import { readLayerSource } from '../../testSupport/readLayerSource.mjs';
 
 function observedShell(t) {
@@ -11,13 +11,14 @@ function observedShell(t) {
   t.after(() => {
     globalThis.window = previous;
   });
-  const followChanged = createEngineEvent();
+  const engine = createFakeEngine();
+  const followChanged = engine.camera.followChanged;
   const shell = {
     generation: 1,
     followChanged,
   };
   const bindings = new LayerBindings({
-    engine: { camera: { followChanged } },
+    engine: engine,
     services: {},
     operations: {
       _stampNavigation() {

src/layers/aircraft/trackedModelFailure.test.mjs

@@ -111,10 +111,8 @@ function viewerAt(height) {
     trackedEntity: undefined,
     entities: { remove() {} },
   };
-  viewer.engine = {
+  viewer.engine = createFakeEngine();
-    isDestroyed: () => false,
+  viewer.engine.fake.script('sampleHeightDetailed', undefined);
-    surface: { tilesLoaded: () => true, sampleHeightDetailed: () => undefined },
-  };
   return viewer;
 }
 

src/layers/aircraft/tracking.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../../globe/testing/fakeEngine.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import * as geo from '../../geo/index.js';
@@ -50,7 +51,7 @@ function harness(layer, { groundM = null, track = [] } = {}) {
     _trailPositions: [],
     _trailBackfillToken: 0,
     _renderer: {
-      engine: {},
+      engine: createFakeEngine(),
       follow: { onChanged: () => () => {} },
     },
   };

src/layers/alpr/overlayInsecureContext.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../../globe/testing/fakeEngine.js';
 // The ALPR paint lane must initialize in an insecure context (plain HTTP over
 // the HOST=0.0.0.0 LAN opt-in), where crypto.randomUUID does not exist.
 import { test } from 'node:test';
@@ -34,7 +35,7 @@ test('ALPR overlay init works without crypto.randomUUID', (t) => {
         },
       },
     },
-    engine: {},
+    engine: createFakeEngine(),
     markers: new Map(),
     syncMarker() {},
     sampleHeight() {},

src/layers/cctv/viewFovy.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../../globe/testing/fakeEngine.js';
 // CCTV icon thinning must use the camera's real vertical FOV. In a 16:9
 // window with Cesium's default fov 60deg the vertical FOV is about 36deg;
 // main read it from viewer.camera.frustum.fovy. Two cameras 17 m apart seen
@@ -33,7 +34,7 @@ test('icon thinning uses the camera vertical FOV, not a pi/3 fallback', () => {
     distance: () => 2000,
     cameraPose: () => pose,
     fovy: () => pose.fovy,
-    engine: { camera: { pose: () => pose } },
+    engine: createFakeEngine({ fovy: FOVY_16_9 }),
   };
   const { refreshHorizonCulling } = createRendering({
     state,

src/layers/earthquakes/edgeCases.test.mjs

@@ -82,7 +82,7 @@ test('edge:earthquakes: an expired record is dropped and a duplicate never forks
     FIXED_SAMPLE,
     WITH_DUPLICATE,
   ]);
-  layer.init(null, { engine: {} });
+  layer.init(null, { engine: createFakeEngine() });
   layer.enable();
   assert.equal(await layer.update(), true);
   assert.equal(await layer.update(), false);

src/layers/firms/viewport.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../../globe/testing/fakeEngine.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import { createViewport } from './viewport.js';
@@ -22,11 +23,14 @@ function harness() {
   const moveEnd = signal(),
     preRender = signal(),
     requests = [];
+  const engine = createFakeEngine();
+  engine.camera.moveEnd = moveEnd;
+  engine.frames.preRender = preRender;
   const layerState = {
     _enabled: true,
     _destroyed: false,
     _view: { camera: {} },
-    _renderer: { engine: { camera: { moveEnd }, frames: { preRender } } },
+    _renderer: { engine: engine },
   };
   const viewport = createViewport({
     layerState,

src/layers/ghostMaps/edgeCases.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../../globe/testing/fakeEngine.js';
 import {
   element,
   kmz,
@@ -74,7 +75,7 @@ function harness(t) {
   let listener = null;
   const layer = createGhostMapsLayer({
     storage: null,
-    createRenderer: (engine) => fakeRenderer(engine.name, live),
+    createRenderer: (engine) => fakeRenderer(engine.kind, live),
     source: {
       getCatalog: async () => catalog('v1'),
       getFile: (_id, version) => files.get(version).promise,
@@ -84,7 +85,7 @@ function harness(t) {
       },
     },
   });
-  layer.init(null, { engine: { name: 'cesium' } });
+  layer.init(null, { engine: createFakeEngine({ kind: 'cesium' }) });
   layer.enable();
   t.after(() => layer.destroy());
   const file = (version) => {
@@ -113,7 +114,7 @@ test('edge:s2-ghostmaps: an edition and engine change mid-parse shows only the s
   await new Promise(setImmediate);
   push(catalog('v3'));
   layer.detachRenderer();
-  await layer.attachRenderer({ engine: { name: 'navara' } });
+  await layer.attachRenderer({ engine: createFakeEngine({ kind: 'navara' }) });
   v2.resolve(kmz('edition two'));
   v3.resolve(kmz('edition three'));
   // Let the queued syncs settle.
@@ -135,7 +136,7 @@ test('edge:s2-ghostmaps: a bad archive keeps the working edition on the globe',
   push(catalog('v2'));
   // The engine changes while the broken file is still on its way.
   layer.detachRenderer();
-  await layer.attachRenderer({ engine: { name: 'navara' } });
+  await layer.attachRenderer({ engine: createFakeEngine({ kind: 'navara' }) });
   broken.resolve(new Uint8Array([1, 2, 3, 4]));
   for (let i = 0; i < 20; i += 1) await new Promise(setImmediate);
 

src/layers/ghostMaps/pendingPaint.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../../globe/testing/fakeEngine.js';
 import {
   element,
   kmz,
@@ -58,10 +59,10 @@ for (const action of ['expire', 'disable']) {
         onClick: () => () => {},
         draw(id, features) {
           const gate = deferred();
-          if (engine.name === 'navara') gates.push(gate);
+          if (engine.kind === 'navara') gates.push(gate);
           else gate.resolve();
           const paint = {
-            engine: engine.name,
+            engine: engine.kind,
             names: [...features.values()].map((feature) => feature.name),
             dropped: [],
             ready: gate.promise,
@@ -84,7 +85,7 @@ for (const action of ['expire', 'disable']) {
         getFile: async () => kmz('old event'),
       },
     });
-    layer.init(null, { engine: { name: 'cesium' } });
+    layer.init(null, { engine: createFakeEngine({ kind: 'cesium' }) });
     layer.enable();
     t.after(() => layer.destroy());
     await layer.update();
@@ -92,7 +93,9 @@ for (const action of ['expire', 'disable']) {
 
     // Engine switch: the new drawing is still decoding its icons.
     layer.detachRenderer();
-    const attached = layer.attachRenderer({ engine: { name: 'navara' } });
+    const attached = layer.attachRenderer({
+      engine: createFakeEngine({ kind: 'navara' }),
+    });
     await new Promise(setImmediate);
     assert.equal(gates.length, 1);
     // The event leaves its age window; the expiry pass runs meanwhile.

src/layers/gnss/ownership.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../../globe/testing/fakeEngine.js';
 import { createGnssDisplay } from './render/display.js';
 import assert from 'node:assert/strict';
 import test from 'node:test';
@@ -82,18 +83,15 @@ const threeHealthy = () => [
 const flush = () => new Promise((resolve) => setImmediate(resolve));
 
 test('a globe-wide rectangle uses the visible screen centre as the query anchor', () => {
-  const anchor = defaultGnssViewAnchor({
+  const engine = createFakeEngine({ width: 1000, height: 800 });
-    host: { size: () => ({ width: 1000, height: 800 }) },
+  engine.fake.script('pickEllipsoid', (pixel) => {
-    camera: {
+    assert.deepEqual(pixel, { x: 500, y: 400 });
-      pickEllipsoid(pixel) {
+    return geo.cartesian3.fromDegrees(-97, 30);
-        assert.deepEqual(pixel, { x: 500, y: 400 });
-        return geo.cartesian3.fromDegrees(-97, 30);
-      },
-      viewRectangle: () => {
-        throw new Error('centre hit must not compute a rectangle');
-      },
-    },
   });
+  engine.fake.script('viewRectangle', () => {
+    throw new Error('centre hit must not compute a rectangle');
+  });
+  const anchor = defaultGnssViewAnchor(engine);
   assert.ok(Math.abs(anchor.latitude - 30) < 1e-8);
   assert.ok(Math.abs(anchor.longitude + 97) < 1e-8);
 });
@@ -189,7 +187,10 @@ test('movement during a pending refresh follows up at the newest view; disable c
 test('the layer requires a snapshot source and cannot be initialized twice', () => {
   assert.throws(() => createGnssIntegrityLayer({}), TypeError);
   const { layer } = harness(async () => ({ rows: [] }));
-  assert.throws(() => layer.init(null, { engine: {} }), /already/);
+  assert.throws(
+    () => layer.init(null, { engine: createFakeEngine() }),
+    /already/,
+  );
 });
 
 test('an enabled refresh bins the snapshot into coloured ground cells', async () => {
@@ -694,19 +695,15 @@ test('the cells stay out of picks', async () => {
 test('view anchor falls back to rectangle, then nadir, then no camera', () => {
   assert.equal(defaultGnssViewAnchor({}), null);
   const radians = geo.math.toRadians;
-  const engine = {
+  const engine = createFakeEngine({ width: 1000, height: 800 });
-    host: { size: () => ({ width: 1000, height: 800 }) },
+  engine.fake.script('pickEllipsoid', undefined);
-    camera: {
+  engine.fake.script('viewRectangle', {
-      pickEllipsoid: () => undefined,
+    west: radians(20),
-      viewRectangle: () => ({
+    south: radians(40),
-        west: radians(20),
+    east: radians(22),
-        south: radians(40),
+    north: radians(42),
-        east: radians(22),
+  });
-        north: radians(42),
+  engine.camera.pose = () => assert.fail('a rectangle must not read the pose');
-      }),
-      pose: () => assert.fail('a rectangle must not read the pose'),
-    },
-  };
   const rectangleAnchor = defaultGnssViewAnchor(engine);
   assert.ok(Math.abs(rectangleAnchor.latitude - 41) < 1e-10);
   assert.ok(Math.abs(rectangleAnchor.longitude - 21) < 1e-10);

src/layers/infrastructure/session.test.mjs

@@ -33,7 +33,7 @@ test('a bundled file delivered between planets keeps multipart IDs and is read o
       lod() {},
     }),
   );
-  layer.init(null, { engine: {} });
+  layer.init(null, { engine: createFakeEngine() });
   const enabled = layer.enable();
   await new Promise(setImmediate);
   layer.detachRenderer();
@@ -57,9 +57,9 @@ test('a bundled file delivered between planets keeps multipart IDs and is read o
   await enabled;
   assert.equal(layer.getAnalystRecords().length, 2);
   assert.equal(captures.length, 0);
-  await layer.attachRenderer({ engine: {} });
+  await layer.attachRenderer({ engine: createFakeEngine() });
   layer.detachRenderer();
-  await layer.attachRenderer({ engine: {} });
+  await layer.attachRenderer({ engine: createFakeEngine() });
   assert.equal(captures[0], captures[1]);
   assert.deepEqual(
     captures[0].records.map((r) => r.id),
@@ -89,13 +89,13 @@ test('a released scene stops waiting for a stalled dataset load, which stays in
       lod() {},
     }),
   );
-  layer.init(null, { engine: {} });
+  layer.init(null, { engine: createFakeEngine() });
   const enabled = layer.enable();
   await new Promise(setImmediate);
   layer.detachRenderer();
   const scene = new AbortController();
   const attaching = layer.attachRenderer({
-    engine: {},
+    engine: createFakeEngine(),
     signal: scene.signal,
   });
   scene.abort();

src/layers/installations/controls.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../../globe/testing/fakeEngine.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import * as geo from '../../geo/index.js';
@@ -26,14 +27,12 @@ test('orbital ground focus reads the drawn height and the engine pick id', () =>
 test('focus frames a selected installation through the globe engine camera', () => {
   const record = { id: 'osm:node:12', latitude: 70, longitude: 179.8 };
   let flight = null;
+  const engine = createFakeEngine();
+  engine.camera.flyToSphere = (sphere, options) => {
+    flight = { sphere, options };
+  };
   const state = {
-    engine: {
+    engine: engine,
-      camera: {
-        flyToSphere: (sphere, options) => {
-          flight = { sphere, options };
-        },
-      },
-    },
     recordById: new Map([[record.id, record]]),
   };
   const controls = createControls({

src/layers/installations/navigation.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../../globe/testing/fakeEngine.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import * as Cesium from 'cesium';
@@ -162,10 +163,12 @@ test('an aborting real ingestion cannot clear the next scheduled view key', asyn
 test('Navara installation ingestion loads from its engine camera without a viewer', async () => {
   const { createIngestion } = await import('./ingestion.js');
   const rectangle = Cesium.Rectangle.fromDegrees(-123, 37, -122, 38);
+  const engine = createFakeEngine({ kind: 'navara' });
+  engine.fake.script('viewRectangle', () => rectangle);
   const state = {
     enabled: true,
     viewer: null,
-    engine: { camera: { viewRectangle: () => rectangle } },
+    engine: engine,
     records: [],
     recordById: new Map(),
     coverage: { kind: 'viewport' },
@@ -242,18 +245,16 @@ test('the engine camera drives installation viewport requests without a viewer',
     east: Cesium.Math.toRadians(-178),
     north: Cesium.Math.toRadians(16),
   };
+  const engine = createFakeEngine();
+  engine.fake.script('viewRectangle', () => rectangle);
+  engine.camera.pose = () => ({
+    position: { x: 1, y: 2, z: 3 },
+    direction: { x: -1, y: 0, z: 0 },
+  });
   const state = {
     enabled: true,
     viewer: null,
-    engine: {
+    engine: engine,
-      camera: {
-        viewRectangle: () => rectangle,
-        pose: () => ({
-          position: { x: 1, y: 2, z: 3 },
-          direction: { x: -1, y: 0, z: 0 },
-        }),
-      },
-    },
   };
   const loads = [];
   const parts = {

src/layers/launches/hover.test.mjs

@@ -1,15 +1,13 @@
+import { createFakeEngine } from '../../globe/testing/fakeEngine.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
-import { createEngineEvent } from '../../globe/contract.js';
 import { createLaunchHover } from './render/display.js';
 
 // What the hover reads of an engine: its canvas, drillPick and camera motion.
 function hoverEngine(drillPick, style = { cursor: '' }) {
-  return {
+  const engine = createFakeEngine({ canvas: { style } });
-    host: { canvas: { style } },
+  engine.fake.script('drillPick', drillPick);
-    picker: { drillPick },
+  return engine;
-    camera: { moveStart: createEngineEvent(), moveEnd: createEngineEvent() },
-  };
 }
 
 function fakeTimers() {

src/layers/launches/launchPadFrame.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../../globe/testing/fakeEngine.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import * as geo from '../../geo/index.js';
@@ -10,12 +11,11 @@ test('selected pad frame uses neutral geometry and the physical orbit epoch', ()
     epoch;
   const state = {
     orbitNow: worldTimeFor('satellites'),
-    _engine: {
+    _engine: createFakeEngine({
-      camera: {
+      longitude: geo.math.toRadians(launch.lon),
-        livePosition: geo.cartesian3.fromDegrees(launch.lon, launch.lat, 500),
+      latitude: geo.math.toRadians(launch.lat),
-        height: () => 500,
+      altitude: 500,
-      },
+    }),
-    },
     _enabled: true,
     _selectedLaunchId: 'qa',
     _launches: [launch],

src/layers/launches/lifecycleSnapshot.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../../globe/testing/fakeEngine.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import { createLifecycle } from './lifecycle.js';
@@ -8,7 +9,7 @@ test('missions preserve the satellite target before their focus flight releases
     let target = 25544,
       snapshot = null;
     const lifecycle = createLifecycle({
-      state: { _engine: {} },
+      state: { _engine: createFakeEngine() },
       services: { render: {} },
       getRenderer: () => ({ setVisible() {} }),
       parts: {
@@ -46,7 +47,7 @@ test('missions begin their entry flight while the satellite catalog loads', asyn
   });
   let flew = false;
   const lifecycle = createLifecycle({
-    state: { _engine: {} },
+    state: { _engine: createFakeEngine() },
     services: { render: {} },
     getRenderer: () => ({ setVisible() {} }),
     parts: {

src/layers/launches/replay.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../../globe/testing/fakeEngine.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import { createState } from './state.js';
@@ -48,9 +49,7 @@ test('changing replay speed during the countdown keeps its real-time liftoff', (
 
 test('resuming a replay restores its retained chase heading', () => {
   const { state } = replayRig();
-  state._engine = {
+  state._engine = createFakeEngine();
-    frames: { preUpdate: { addEventListener: () => () => {} } },
-  };
   state._launches = [{ id: 'mission' }];
   state._replayCameraLaunchId = 'mission';
   state._replayCameraHeading = 1.2;

src/layers/localAdsb/models.test.mjs

@@ -26,7 +26,7 @@ test('ground snapping excludes the aircraft by its engine pick id', async () =>
       },
       frustumTester: () => () => true,
       horizon: () => ({ isPointVisible: () => true }),
-      engine: {},
+      engine: createFakeEngine(),
     },
   };
   const exclusions = [];

src/layers/recentImagery/index.test.mjs

@@ -728,14 +728,12 @@ function failingMapController() {
   const controller = new MapSourceController({
     registry,
     initialStack: 'photoreal',
-    engine: {
+    engine: Object.assign(createFakeEngine(), {
-      kind: 'cesium',
-      render: { request() {} },
       maps: createCesiumMaps(viewer, {
         credits: createCesiumCredits(viewer).credits,
         createImageryLayer: (provider) => ({ provider }),
       }).maps,
-    },
+    }),
     onError: () => {},
   });
   const calls = [];

src/layers/satellites/detachedToggle.test.mjs

@@ -93,7 +93,7 @@ test('restored orbit rings receive their current rotation before the first frame
     },
   });
   lifecycle.methods.attachRenderer({
-    engine: {},
+    engine: createFakeEngine(),
     viewRestored: new Promise(() => {}),
   });
   assert.equal(rotated, 1);

src/layers/traffic/deadline.test.mjs

@@ -13,21 +13,16 @@ import { createFakeEngine } from '../../globe/testing/fakeEngine.js';
 // the near plane, as the engines answer).
 function cameraEngine(scene) {
   const eye = new C.Cartesian3();
-  return {
+  const engine = createFakeEngine({
-    host: {
+    width: scene.canvas.clientWidth,
-      size: () => ({
+    height: scene.canvas.clientHeight,
-        width: scene.canvas.clientWidth,
+  });
-        height: scene.canvas.clientHeight,
+  engine.fake.script('worldToWindow', (point, result) => {
-      }),
+    C.Matrix4.multiplyByPoint(scene.camera.viewMatrix, point, eye);
-    },
+    if (eye.z >= -scene.camera.frustum.near) return undefined;
-    projector: {
+    return C.SceneTransforms.worldToWindowCoordinates(scene, point, result);
-      worldToWindow(point, result) {
+  });
-        C.Matrix4.multiplyByPoint(scene.camera.viewMatrix, point, eye);
+  return engine;
-        if (eye.z >= -scene.camera.frustum.near) return undefined;
-        return C.SceneTransforms.worldToWindowCoordinates(scene, point, result);
-      },
-    },
-  };
 }
 
 const bounds = { west: 0, east: 0.01, south: 0, north: 0.01 };

src/layers/traffic/footprint.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../../globe/testing/fakeEngine.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import * as geo from '../../geo/index.js';
@@ -35,32 +36,35 @@ test('oblique horizon bearings are bounded and tile caps hold at city latitudes'
   ]) {
     // An engine-shaped stub: the camera's pose and its ellipsoid and ray
     // picks (the sky above the 300 px line), and the canvas.
-    const engine = {
+    const engine = createFakeEngine({
-      camera: {
+      longitude: geo.math.toRadians(lon),
-        pose: () => ({
+      latitude: geo.math.toRadians(lat),
-          cartographic: geo.cartographic.fromDegrees(lon, lat, 300),
+      altitude: 300,
-          heading: 0,
+      canvas: { width: 1280, height: 800 },
-          pitch: -Math.PI / 12,
+    });
-        }),
+    engine.fake.setPose({
-        pickEllipsoid(p) {
+      longitude: geo.math.toRadians(lon),
-          if (p.y < 300) return undefined;
+      latitude: geo.math.toRadians(lat),
-          return geo.cartesian3.fromDegrees(
+      height: 300,
-            lon + (p.x - 640) / 100000,
+      heading: 0,
-            lat + (800 - p.y) / 50000,
+      pitch: -Math.PI / 12,
-            0,
+    });
-          );
+    engine.fake.script('pickEllipsoid', (p) => {
-        },
+      if (p.y < 300) return undefined;
-        pickRay: () => ({
+      return geo.cartesian3.fromDegrees(
-          origin: geo.cartesian3.create(),
+        lon + (p.x - 640) / 100000,
-          direction: geo.cartesian3.create(
+        lat + (800 - p.y) / 50000,
-            -Math.sin((lat * Math.PI) / 180) * Math.cos((lon * Math.PI) / 180),
+        0,
-            -Math.sin((lat * Math.PI) / 180) * Math.sin((lon * Math.PI) / 180),
+      );
-            Math.cos((lat * Math.PI) / 180),
+    });
-          ),
+    engine.camera.pickRay = () => ({
-        }),
+      origin: geo.cartesian3.create(),
-      },
+      direction: geo.cartesian3.create(
-      host: { canvas: { width: 1280, height: 800 } },
+        -Math.sin((lat * Math.PI) / 180) * Math.cos((lon * Math.PI) / 180),
-    };
+        -Math.sin((lat * Math.PI) / 180) * Math.sin((lon * Math.PI) / 180),
+        Math.cos((lat * Math.PI) / 180),
+      ),
+    });
     const result = createReticleFootprint()(engine, 300);
     assert.ok(result.coverage.coarse.length <= 16);
     assert.ok(result.coverage.detail.length <= 16);

src/layers/transit/lifecycle.test.mjs

@@ -3695,12 +3695,12 @@ test('actual Traffic, Bikeshare and Transit lifecycles retain sensitivity in eve
   // Traffic claims through its engine's camera, as bikeshare does: the
   // viewer's. The stub has what binding its scene subscribes to.
   const listeners = { addEventListener: () => noop };
-  const trafficEngine = {
+  const trafficEngine = createFakeEngine();
-    camera: app.viewer.camera,
+  trafficEngine.camera = app.engine.camera;
-    frames: { preRender: listeners, postRender: listeners },
+  trafficEngine.frames.preRender = listeners;
-    projector: { viewProjection: noop },
+  trafficEngine.frames.postRender = listeners;
-    surface: { tilesLoaded: () => false },
+  trafficEngine.projector.viewProjection = noop;
-  };
+  trafficEngine.fake.script('tilesLoaded', false);
   const traffic = trafficLifecycle({
     state: { _engine: trafficEngine, _loadGeneration: 0 },
     services: {

src/layers/wind/edgeCases.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../../globe/testing/fakeEngine.js';
 // Edge cases for wind: on a fixed
 // grid direction, speed and legend agree whichever way the centre is picked,
 // and an empty field is never presented as calm.
@@ -24,15 +25,13 @@ const options = {
   status: 'Model forecast',
 };
 /** Inspect either the current map centre or a captured position. */
-const viaEngine = (snapshot, point) =>
+const viaEngine = (snapshot, point) => {
-  inspectWindAtCenter(
+  const engine = createFakeEngine({
-    snapshot,
+    canvas: { clientWidth: 800, clientHeight: 600 },
-    {
+  });
-      camera: { pickEllipsoid: () => point },
+  engine.fake.script('pickEllipsoid', point);
-      host: { canvas: { clientWidth: 800, clientHeight: 600 } },
+  return inspectWindAtCenter(snapshot, engine, options);
-    },
+};
-    options,
-  );
 const viaPosition = (snapshot, point) =>
   inspectWindAtCenter(snapshot, null, { ...options, position: point });
 const windLine = (reading) =>

src/layers/wind/inspection.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../../globe/testing/fakeEngine.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import * as geo from '../../geo/index.js';
@@ -27,10 +28,10 @@ test('center inspection uses a fixed forecast reading without double-converting
       values: Float32Array.from([20, 20, 20, 20]),
     },
   };
-  const engine = {
+  const engine = createFakeEngine({
-    camera: { pickEllipsoid: () => geo.cartesian3.fromDegrees(0, 0) },
+    canvas: { clientWidth: 800, clientHeight: 600 },
-    host: { canvas: { clientWidth: 800, clientHeight: 600 } },
+  });
-  };
+  engine.fake.script('pickEllipsoid', () => geo.cartesian3.fromDegrees(0, 0));
   const result = inspectWindAtCenter(snapshot, engine, {
     overlay: 'temperature',
     units: 'km/h',

src/layers/wind/inspectionMarker.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../../globe/testing/fakeEngine.js';
 // src/layers/wind/inspectionMarker.test.mjs — the wind inspection marker
 // follows only its captured point, renders in its container, and releases
 // its frame listener.
@@ -47,15 +48,13 @@ function fixture(t) {
       requestRender() {},
     },
   };
-  const engine = {
+  const engine = createFakeEngine({ canvas: viewer.scene.canvas });
-    host: { canvas: viewer.scene.canvas },
+  engine.frames.postRender = viewer.scene.postRender;
-    frames: { postRender: viewer.scene.postRender },
+  engine.fake.script(
-    projector: {
+    'worldToWindow',
-      worldToWindow: viewer.scene.cartesianToCanvasCoordinates,
+    viewer.scene.cartesianToCanvasCoordinates,
-      horizonVisible: () => visibility.visible,
+  );
-    },
+  engine.projector.horizonVisible = () => visibility.visible;
-    render: { request() {} },
-  };
   const store = useWindInspectionStore(pinia);
   visibility.visible = true;
   const owner = createWindInspectionMarker({

src/maps/controller.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import { createCesiumMaps } from '../globe/cesium/maps.js';
 import { createCesiumCredits } from '../globe/cesium/credits.js';
 import test from 'node:test';
@@ -72,7 +73,7 @@ function fixture(registry, options = {}) {
   });
   const controller = new MapSourceController({
     registry,
-    engine: { kind: 'cesium', render: { request() {} }, maps: mapsOwner.maps },
+    engine: Object.assign(createFakeEngine(), { maps: mapsOwner.maps }),
     onChange: (state) => changes.push(state),
     ...options,
   });

src/scenes/director.test.mjs

@@ -2070,7 +2070,7 @@ test('a caught run failure resolves as run-failed, not success (#971)', async ()
 test('a failed scene-pack rebind releases the partial renderer and a stopped shot unblocks', async () => {
   const director = Object.create(SceneDirector.prototype);
   const drawn = new Set();
-  director.engine = { host: { container: {} } };
+  director.engine = createFakeEngine();
   director._dataPacks = {
     setScene(viewer) {
       if (!viewer) drawn.clear();
@@ -2088,7 +2088,7 @@ test('a failed scene-pack rebind releases the partial renderer and a stopped sho
   assert.throws(
     () =>
       director.attachScene(
-        { engine: { host: { container: {} } } },
+        { engine: createFakeEngine() },
         {},
         () => true,
       ),
@@ -2100,7 +2100,7 @@ test('a failed scene-pack rebind releases the partial renderer and a stopped sho
   abort.abort();
   assert.equal(await stopped, false);
   const waiting = director._waitForScene();
-  director.engine = { host: {} };
+  director.engine = createFakeEngine();
   director.styleManager = {};
   director.resumeScene();
   assert.equal(await waiting, true);

src/scopeMask.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from './globe/testing/fakeEngine.js';
 import { test, beforeEach } from 'node:test';
 import assert from 'node:assert/strict';
 import {
@@ -242,7 +243,9 @@ test('scope appearance follows direct state changes and install/destroy lifecycl
     setScopeMaskEnabled(false);
     assert.equal(dom.documentElement.dataset.scopeMask, 'off');
     delete dom.documentElement.dataset.scopeMask;
-    installScopeMask({ host: { container: dom.container } });
+    installScopeMask(
+      createFakeEngine({ container: dom.container, altitude: 14_000_000 }),
+    );
     assert.equal(
       dom.documentElement.dataset.scopeMask,
       'off',
@@ -254,7 +257,9 @@ test('scope appearance follows direct state changes and install/destroy lifecycl
       undefined,
       'destroy clears the document marker',
     );
-    installScopeMask({ host: { container: dom.container } });
+    installScopeMask(
+      createFakeEngine({ container: dom.container, altitude: 14_000_000 }),
+    );
     assert.equal(
       dom.documentElement.dataset.scopeMask,
       'off',
@@ -282,7 +287,9 @@ test('scope appearance follows direct state changes and install/destroy lifecycl
 test('a DPR change with no resize still repaints the backing store', () => {
   const dom = stubScopeMaskDom({ width: 1000, height: 800, dpr: 1 });
   try {
-    installScopeMask({ host: { container: dom.container } });
+    installScopeMask(
+      createFakeEngine({ container: dom.container, altitude: 14_000_000 }),
+    );
     // 1x monitor: backing store matches CSS pixels.
     assert.equal(dom.canvas.width, 1000);
     assert.equal(dom.canvas.height, 800);
@@ -314,7 +321,9 @@ test('a DPR change with no resize still repaints the backing store', () => {
 test('destroy tears the DPR watch down (no redraw after teardown)', () => {
   const dom = stubScopeMaskDom({ width: 640, height: 480, dpr: 1 });
   try {
-    installScopeMask({ host: { container: dom.container } });
+    installScopeMask(
+      createFakeEngine({ container: dom.container, altitude: 14_000_000 }),
+    );
     assert.equal(dom.canvas.width, 640);
     destroyScopeMask();
     dom.setDpr(2);
@@ -439,7 +448,9 @@ test('quantization snaps to the repaint grid', () => {
 test('repaint gate: only a QUANTIZED step repaints; hovering costs nothing', () => {
   const dom = stubScopeMaskDom({ width: 1000, height: 800, dpr: 1 });
   try {
-    installScopeMask({ host: { container: dom.container } });
+    installScopeMask(
+      createFakeEngine({ container: dom.container, altitude: 14_000_000 }),
+    );
     const base = getScopeTerminusRepaintCount();
 
     // Parked at true full-globe altitude: the seeded alpha already matches, so
@@ -477,7 +488,9 @@ test('repaint gate: only a QUANTIZED step repaints; hovering costs nothing', ()
 test('a full zoom-in gesture costs only a handful of repaints', () => {
   const dom = stubScopeMaskDom({ width: 1000, height: 800, dpr: 1 });
   try {
-    installScopeMask({ host: { container: dom.container } });
+    installScopeMask(
+      createFakeEngine({ container: dom.container, altitude: 14_000_000 }),
+    );
     const base = getScopeTerminusRepaintCount();
 
     // 20 Mm → ground in 10 km steps: ~2000 samples across the whole descent,
@@ -510,7 +523,9 @@ test('a full zoom-in gesture costs only a handful of repaints', () => {
 test('an override pins the terminus and null restores the ramp', () => {
   const dom = stubScopeMaskDom({ width: 1000, height: 800, dpr: 1 });
   try {
-    installScopeMask({ host: { container: dom.container } });
+    installScopeMask(
+      createFakeEngine({ container: dom.container, altitude: 14_000_000 }),
+    );
     setScopeTerminusOverride(0.97);
     assert.equal(getScopeTerminusOverride(), 0.97);
     assert.equal(getScopeTerminusAlpha(), 0.97);
@@ -536,7 +551,9 @@ test('an override pins the terminus and null restores the ramp', () => {
 test('the hard-crop (feather 0) path honors the same terminus alpha', () => {
   const dom = stubScopeMaskDom({ width: 1000, height: 800, dpr: 1 });
   try {
-    installScopeMask({ host: { container: dom.container } });
+    installScopeMask(
+      createFakeEngine({ container: dom.container, altitude: 14_000_000 }),
+    );
     updateScopeTerminusForHeight(SCOPE_TERMINUS_FAR_M + 5_000_000); // true full-globe view
     setScopeMaskFeather(0); // hard crop — the evenodd rect-minus-circle path
     // The globe-scale seed paint is legitimately in the history, so assert on
@@ -583,15 +600,12 @@ function stubScopeEngine(container, heightM) {
     set.add(listener);
     return () => set.delete(listener);
   };
+  const engine = createFakeEngine({ container, altitude: height });
+  engine.frames.preRender.addEventListener = addTo(preRenderListeners);
+  engine.camera.moveEnd.addEventListener = addTo(moveEndListeners);
+  engine.camera.height = () => height;
   return {
-    engine: {
+    engine,
-      host: { container },
-      frames: { preRender: { addEventListener: addTo(preRenderListeners) } },
-      camera: {
-        height: () => height,
-        moveEnd: { addEventListener: addTo(moveEndListeners) },
-      },
-    },
     setHeight(next) {
       height = next;
     },
@@ -748,7 +762,9 @@ test('terminus percents clamp into the supported band; junk is absent, not zero'
 test('a pinned override is floored to the band at every entry point', () => {
   const dom = stubScopeMaskDom({ width: 1000, height: 800, dpr: 1 });
   try {
-    installScopeMask({ host: { container: dom.container } });
+    installScopeMask(
+      createFakeEngine({ container: dom.container, altitude: 14_000_000 }),
+    );
     setScopeTerminusOverride(0); // an sce=0 link, or any stale caller
     assert.equal(
       getScopeTerminusOverride(),

src/standalone/applicationSwitch.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 // The standalone application is created once; an engine switch detaches and
 // attaches only its engine-bound parts. A candidate that fails releases its
 // renderer, and the working engine attaches again on the same parts.
@@ -48,7 +49,8 @@ function standalone({ failOpen = null, beforeOpen, beforeRelease, lifecycle = fa
     createStandaloneScene: async ({ engineKind, defer }) => {
       await beforeOpen?.(engineKind);
       if (failOpen === engineKind) throw new Error(`${engineKind} refused`);
-      const engine = { kind: engineKind, id: opened.length };
+      const engine = createFakeEngine({ kind: engineKind });
+      engine.id = opened.length;
       opened.push(engine);
       defer(async () => {
         await beforeRelease?.(engine);

src/standalone/engineSwitch.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import { createSessionHandoff } from '../app/sessionHandoff.js';
 import assert from 'node:assert/strict';
 import test from 'node:test';
@@ -479,10 +480,7 @@ test('pagehide while the outgoing engine is released starts nothing', async () =
 
 test('a slow first frame never rolls back a started engine', async () => {
   const timers = [];
-  const engine = {
+  const engine = createFakeEngine();
-    frames: { postRender: { addEventListener: () => () => {} } },
-    render: { request() {} },
-  };
   const h = harness();
   let frame;
   const machine = createEngineSwitch({
@@ -525,21 +523,12 @@ test('the first-frame wait resolves on a frame, on a hidden tab and on timeout',
   };
   let draw;
   let requests = 0;
-  const engine = {
+  const engine = createFakeEngine();
-    frames: {
+  engine.frames.postRender.addEventListener = (fn) => {
-      postRender: {
+    draw = fn;
-        addEventListener(fn) {
+    return () => { draw = null; };
-          draw = fn;
-          return () => {
-            draw = null;
-          };
-        },
-      },
-    },
-    render: {
-      request: () => requests++,
-    },
   };
+  engine.render.request = () => requests++;
   const timers = new Map();
   const options = {
     document: doc,

src/standalone/rendererCache.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import assert from 'node:assert/strict';
 import test from 'node:test';
 import { createRendererCache } from './rendererCache.js';
@@ -51,10 +52,7 @@ function fakeBuild(released) {
       resume() {
         this.running = true;
       },
-      engine: {
+      engine: createFakeEngine({ container, canvas }),
-        host: { container, canvas },
-        render: { request() {} },
-      },
     };
   };
 }

src/standalone/sceneSwitcher.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import { createSceneSwitcher } from './sceneSwitcher.js';
@@ -193,7 +194,7 @@ test('the restored camera precedes retained follow and replay', async () => {
   const app = {
     getState: () => ({ status: 'ready' }),
     getComponents: () => ({
-      scene: { engine: { kind: current } },
+      scene: { engine: createFakeEngine({ kind: current }) },
       controls: { styleManager: style },
     }),
     async detachScene() {

src/ui/displayPanel.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 // src/ui/displayPanel.test.mjs — the Display panel renders bloom and sharpen
 // from what VisualSettings publishes, and shows its initial markup before.
 import '../testSupport/registerDom.mjs';
@@ -145,6 +146,7 @@ test('a publish never rewrites a slider the user is dragging', async (t) => {
 /** VisualSettings with a stand-in detection engine. */
 function detectionSettings(store) {
   const { owner } = settings(store);
+  // This is detection state, not a globe engine.
   const engine = {
     mode: 'OFF',
     tuning: { densityPct: 50, allocationStrategy: 'ELASTIC' },
@@ -425,12 +427,7 @@ test('the imported files render what the file import publishes and keep focus',
   assert.equal($('geo-import-hint').textContent, '');
 
   // A globe engine double the files draw on.
-  const engine = {
+  const engine = createFakeEngine({ container: document.createElement('div') });
-    host: { container: document.createElement('div'), canvas: null },
-    camera: { moveEnd: { addEventListener: () => () => {} } },
-    surface: { tilesLoaded: () => true },
-    render: { request() {} },
-  };
   const tool = createGeoFileImport({
     drawFile: async () => ({
       report: { undrawn: 0 },

src/ui/frameRateMonitor.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import { createFrameRateMonitor } from './frameRateMonitor.js';
@@ -17,15 +18,10 @@ function fixture(t) {
     addEventListener: (name, handler) => keys.add(handler),
     removeEventListener: (name, handler) => keys.delete(handler),
   };
-  const engine = {
+  const engine = createFakeEngine();
-    frames: {
+  engine.frames.postRender.addEventListener = (handler) => {
-      postRender: {
+    frames.add(handler);
-        addEventListener(handler) {
+    return () => frames.delete(handler);
-          frames.add(handler);
-          return () => frames.delete(handler);
-        },
-      },
-    },
   };
   const monitor = createFrameRateMonitor({ engine, documentRef, store });
   t.after(() => monitor.destroy());
@@ -108,7 +104,7 @@ test('a page without the title bar gets no readout and keeps the key', () => {
   let listened = false;
   const store = { publishFps: () => assert.fail('nothing to show it in') };
   const monitor = createFrameRateMonitor({
-    engine: { frames: { postRender: { addEventListener: () => () => {} } } },
+    engine: createFakeEngine(),
     documentRef: {
       getElementById: () => null,
       addEventListener: () => (listened = true),
@@ -130,9 +126,7 @@ test("destroying an earlier monitor leaves a newer one's readout", () => {
     addEventListener() {},
     removeEventListener() {},
   };
-  const engine = {
+  const engine = createFakeEngine();
-    frames: { postRender: { addEventListener: () => () => {} } },
-  };
   const first = createFrameRateMonitor({ engine, documentRef, store });
   const second = createFrameRateMonitor({ engine, documentRef, store });
   const shown = store.fps;

src/ui/frameRateView.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 // src/ui/frameRateView.test.mjs — the title bar's FPS readout renders what
 // createFrameRateMonitor() publishes and toggles with the backquote key.
 import '../testSupport/registerDom.mjs';
@@ -19,7 +20,7 @@ test('the FPS readout sits in the title bar, hidden until the backquote key', as
     document.querySelector('#title-bar .frame-rate-readout');
   assert.equal(readout(), null, 'no readout without a monitor');
   const monitor = createFrameRateMonitor({
-    engine: { frames: { postRender: { addEventListener: () => () => {} } } },
+    engine: createFakeEngine(),
     store: useStatusStore(pinia),
   });
   t.after(() => monitor.destroy());

src/ui/geoFileImport.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 // Behavioral tests for DISPLAY ▸ Import: the controller is driven against
 // fake DOM and engine doubles with an injected loader and drawing, and its
 // observable effects are asserted — drawings made and destroyed, the rows
@@ -65,22 +66,18 @@ class FakeElement {
 /** A globe engine double: its host, camera moves and render requests. */
 function fakeEngine() {
   const moveEnd = new Set();
-  const engine = {
+  const engine = createFakeEngine({
     kind: 'fake',
-    host: {
+    container: new FakeElement('div', 'cesiumContainer'),
-      container: new FakeElement('div', 'cesiumContainer'),
+    canvas: new FakeElement('canvas'),
-      canvas: new FakeElement('canvas'),
+  });
-    },
+  engine.camera.moveEnd.addEventListener = (fn) => (
-    camera: {
+    moveEnd.add(fn),
-      moveEnd: {
+    () => moveEnd.delete(fn)
-        addEventListener: (fn) => (moveEnd.add(fn), () => moveEnd.delete(fn)),
+  );
-      },
+  engine.renders = 0;
-    },
+  engine.render.request = () => (engine.renders += 1);
-    surface: { tilesLoaded: () => true },
+  engine.moveEnd = moveEnd;
-    renders: 0,
-    render: { request: () => (engine.renders += 1) },
-    moveEnd,
-  };
   return engine;
 }
 

src/ui/geoFileImportRedraw.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 // A file removed while its drawing on the next engine is still pending
 // (icon decode) must not leave that drawing on the globe.
 import test from 'node:test';
@@ -10,12 +11,7 @@ const el = () => ({
   addEventListener() {},
   removeEventListener() {},
 });
-const engine = () => ({
+const engine = () => createFakeEngine({ container: el(), canvas: el() });
-  host: { container: el(), canvas: el() },
-  camera: { moveEnd: { addEventListener: () => () => {} } },
-  surface: { tilesLoaded: () => true },
-  render: { request() {} },
-});
 
 test('removing a file during its redraw destroys the late drawing', async () => {
   const document = {

src/ui/shareLinks.test.mjs

@@ -445,16 +445,13 @@ test('the followed entity is read in the share format, and its offset round-trip
       gevDisplayPosition: () => target,
     },
   };
-  const engine = {
+  const engine = createFakeEngine();
-    camera: {
+  engine.fake.setPose({ position: cameraPosition });
-      pose: () => ({ position: cameraPosition }),
+  engine.camera.following = () =>
-      following: () =>
+    viewer.trackedEntity && {
-        viewer.trackedEntity && {
+      native: viewer.trackedEntity,
-          native: viewer.trackedEntity,
+      target: () => target,
-          target: () => target,
+    };
-        },
-    },
-  };
   const subject = readShareFollowSubject({ engine, nowMs: NOW_MS });
   assert.equal(subject.kind, 'military_aircraft');
   assert.equal(subject.id, 'ae1234');

src/ui/shellLifetime.test.mjs

@@ -127,12 +127,11 @@ test('camera-entry listeners are removed before any asynchronous layer cleanup',
   const { owner } = bindings(t);
   let changes = 0;
   let trackedCallback;
-  owner.engine = { camera: { followChanged: {
+  owner.engine = createFakeEngine();
-    addEventListener(callback) {
+  owner.engine.camera.followChanged.addEventListener = (callback) => {
-      trackedCallback = callback;
+    trackedCallback = callback;
-      return () => { changes += 1; };
+    return () => { changes += 1; };
-    },
+  };
-  } } };
   owner._stampNavigation = () => { changes += 100; };
   owner.observeCamera();
   owner.stop();

src/ui/shellSceneSwap.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 // The shell lives for the page: an engine switch detaches only its
 // globe-bound parts and attaches them to the next globe, keeping the shell's
 // session objects (navigation, location search, HUD, share link, display
@@ -37,7 +38,7 @@ function fakeShell() {
     },
   };
   Object.assign(shell, {
-    _scene: { viewer: {}, engine: { kind: 'cesium' }, mapStackController: {} },
+    _scene: { viewer: {}, engine: createFakeEngine({ kind: 'cesium' }), mapStackController: {} },
     _disposed: false,
     _layerSession: null,
     services: {
@@ -143,7 +144,7 @@ test('the next globe gets new globe-bound parts and the restore runs on it', asy
   const { shell, session, log } = fakeShell();
   await shell.detachScene({ handoff: true });
   log.length = 0;
-  const engine = { kind: 'navara' };
+  const engine = createFakeEngine({ kind: 'navara' });
   await shell.attachScene({
     viewer: null,
     engine,
@@ -176,7 +177,7 @@ test('the next globe gets new globe-bound parts and the restore runs on it', asy
   assert.equal(shell._navigation, session.navigation);
   await shell.attachScene({ engine });
   await assert.rejects(
-    shell.attachScene({ engine: { kind: 'cesium' } }),
+    shell.attachScene({ engine: createFakeEngine({ kind: 'cesium' }) }),
     /attached to a globe/,
   );
 });
@@ -186,7 +187,7 @@ test('a panel whose layer is another instance in the new catalog is rebuilt', as
   await shell.detachScene({ handoff: true });
   log.length = 0;
   await shell.attachScene({
-    engine: { kind: 'cesium' },
+    engine: createFakeEngine({ kind: 'cesium' }),
     services: { cctvLayer: 'other' },
   });
   assert.ok(log.includes('_initCctvPanel'));
@@ -209,7 +210,7 @@ test('an attachment that throws part-way leaves the shell detached and attachabl
     throw new Error('overlay host failed');
   };
   await assert.rejects(
-    shell.attachScene({ engine: { kind: 'navara' } }),
+    shell.attachScene({ engine: createFakeEngine({ kind: 'navara' }) }),
     /overlay host failed/,
   );
   // The shell releases what it built and is detached when that settles.
@@ -217,7 +218,7 @@ test('an attachment that throws part-way leaves the shell detached and attachabl
   assert.equal(shell.engine, null);
   log.length = 0;
   shell._initSceneOverlays = () => log.push('_initSceneOverlays');
-  const engine = { kind: 'cesium' };
+  const engine = createFakeEngine({ kind: 'cesium' });
   await shell.attachScene({ engine });
   assert.equal(shell.engine, engine);
   assert.ok(log.includes('shareRestoration.start'));
@@ -244,7 +245,7 @@ test('between engines a style key waits for the next engine instead of the relea
     shell._layerBindings = { observeCamera() {}, stop() {}, disconnect() {} };
     shell._visualSettings = { setStyle: (name) => applied.push(name) };
   };
-  await shell.attachScene({ engine: { kind: 'cesium' } });
+  await shell.attachScene({ engine: createFakeEngine({ kind: 'cesium' }) });
   await Promise.resolve();
   await Promise.resolve();
   assert.deepEqual(applied, ['crt']);
@@ -262,13 +263,13 @@ test('shell recovery waits for failed attachment cleanup and serializes repeated
   shell._initSceneOverlays = () => {
     throw new Error('overlay failed');
   };
-  const failed = shell.attachScene({ engine: { kind: 'navara' } });
+  const failed = shell.attachScene({ engine: createFakeEngine({ kind: 'navara' }) });
   const rejected = assert.rejects(failed, /overlay failed/);
   await Promise.resolve();
   const detach = shell.detachScene();
   const again = shell.detachScene();
   shell._initSceneOverlays = () => {};
-  const engine = { kind: 'cesium' };
+  const engine = createFakeEngine({ kind: 'cesium' });
   const recovered = shell.attachScene({ engine });
   await Promise.resolve();
   assert.notEqual(shell.engine, engine, 'recovery waits for cleanup');
@@ -288,7 +289,7 @@ test('shell attach waits for a deferred outgoing detach', async () => {
       release = resolve;
     });
   const leaving = shell.detachScene({ handoff: true });
-  const engine = { kind: 'navara' };
+  const engine = createFakeEngine({ kind: 'navara' });
   const entering = shell.attachScene({ engine });
   await Promise.resolve();
   assert.notEqual(shell.engine, engine);
@@ -302,7 +303,7 @@ test('an engine without Wildlife Sightings gets no card instead of a failed star
   // The stand-in a catalog gives for a layer the engine leaves out.
   Object.assign(shell, {
     services: { wildlifeSightingsLayer: {} },
-    _scene: { viewer: null, engine: { kind: 'navara' } },
+    _scene: { viewer: null, engine: createFakeEngine({ kind: 'navara' }) },
   });
   assert.doesNotThrow(() => shell._initWildlifeSightingCard());
   assert.equal(shell._wildlifeSightingCard, null);
@@ -324,7 +325,7 @@ test('a hosted shell uses the enclosing transition while direct calls wait outsi
     entered();
     return new Promise((resolve) => { release = resolve; });
   };
-  const next = { engine: { kind: 'navara' }, catalog };
+  const next = { engine: createFakeEngine({ kind: 'navara' }), catalog };
   const switching = host.run(async (transaction) => {
     await host.detach({ handoff: true }, transaction);
     await host.attach(next, transaction);

src/ui/stateOwners.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import assert from 'node:assert/strict';
 import test from 'node:test';
 import { NavigationController } from './navigationController.js';
@@ -69,7 +70,7 @@ test('share teardown settles its promise, removes gestures and rejects a retaine
   let stamps = 0;
   let applies = 0;
   const owner = new ShareRestoration({
-    engine: { host: { canvas } },
+    engine: createFakeEngine({ canvas }),
     navigation: {
       _beginDeferredNavigation: () => 1,
       _reassertNavigationHandoff: () => true,
@@ -164,12 +165,11 @@ test('on Navara, presets set the Sharpen slider to 80 % and the engine draws it'
     _sharpenSliderRow: element(),
     _sharpenSliderValue: element(),
   };
+  const engine = createFakeEngine({ kind: 'navara' });
+  engine.render.setSharpen = (options) => sharpen.push(options);
   const owner = new VisualSettings({
     viewer: null,
-    engine: {
+    engine: engine,
-      kind: 'navara',
-      render: { setSharpen: (options) => sharpen.push(options) },
-    },
     elements,
     operations: {
       _syncShareState() {},

src/ui/visualEffects.test.mjs

@@ -57,7 +57,7 @@ function fixture() {
       createStage: (options) => ({ ...options, enabled: true }),
     },
   );
-  const engine = { render: cesium.render, isDestroyed: () => false };
+  const engine = Object.assign(createFakeEngine(), { render: cesium.render });
   const effects = new VisualEffects({
     engine,
     requestRender: (reason) => requests.push(reason),
@@ -351,9 +351,8 @@ test('existing baseline and military presets keep one detection default', () =>
 test('an engine sharpens with the same amount scale, only while on and above 0', () => {
   const sharpen = [];
   const requests = [];
-  const engine = {
+  const engine = createFakeEngine();
-    render: { setSharpen: (options) => sharpen.push(options) },
+  engine.render.setSharpen = (options) => sharpen.push(options);
-  };
   const effects = new VisualEffects({
     engine,
     requestRender: (reason) => requests.push(reason),

src/voice/gevRealtime.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 // Pure-logic unit tests for the voice-lifecycle size guards (Batch 11, M13).
 // These helpers are DOM/WebRTC-free so they pin the screenshot down-scaling and
 // payload-byte estimation that keep an oversized dc.send from stranding a turn.
@@ -2859,10 +2860,8 @@ test('isBenignViewportDeleteError is false for non-error payloads and junk', ()
 test('hidden document yields no fresh frame — capture must not label a stale canvas Current', async () => {
   const originalDocument = globalThis.document;
   let requested = 0;
-  const engine = {
+  const engine = createFakeEngine();
-    frames: { postRender: { addEventListener() { return () => {}; } } },
+  engine.render.request = () => { requested += 1; };
-    render: { request() { requested += 1; } },
-  };
   try {
     globalThis.document = { hidden: true };
     const fresh = await renderFreshCesiumFrame(engine);
@@ -2878,10 +2877,9 @@ test('visible document with a rendering scene reports a fresh frame', async () =
   try {
     globalThis.document = { hidden: false };
     let fire = null;
-    const engine = {
+    const engine = createFakeEngine();
-      frames: { postRender: { addEventListener(listener) { fire = listener; return () => { fire = null; }; } } },
+    engine.frames.postRender.addEventListener = (listener) => { fire = listener; return () => { fire = null; }; };
-      render: { request() { queueMicrotask(() => fire?.()); } },
+    engine.render.request = () => { queueMicrotask(() => fire?.()); };
-    };
     const fresh = await renderFreshCesiumFrame(engine);
     assert.equal(fresh, true);
   } finally {
@@ -2895,10 +2893,9 @@ test('a tab switch during the bounded render wait invalidates freshness', async
     const doc = { hidden: false };
     globalThis.document = doc;
     let fire = null;
-    const engine = {
+    const engine = createFakeEngine();
-      frames: { postRender: { addEventListener(listener) { fire = listener; return () => { fire = null; }; } } },
+    engine.frames.postRender.addEventListener = (listener) => { fire = listener; return () => { fire = null; }; };
-      render: { request() { doc.hidden = true; queueMicrotask(() => fire?.()); } },
+    engine.render.request = () => { doc.hidden = true; queueMicrotask(() => fire?.()); };
-    };
     const fresh = await renderFreshCesiumFrame(engine);
     assert.equal(fresh, false, 'freshness rechecked after the await');
   } finally {

src/voice/integrationContract.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 // Cross-feature voice contracts, driven through the real action runner:
 // one result contract (engine fields → model payload → voice card), shared
 // pointing for imagery, result-set ownership between OSM and the analyst,
@@ -687,7 +688,7 @@ test('an engine switch keeps the last answer for a follow-up on the next engine'
     build: () =>
       harness({ runnerOptions: { analystMemory, layerEnabledAt } }).runner,
   });
-  run.attach({ engine: { kind: 'cesium' } });
+  run.attach({ engine: createFakeEngine({ kind: 'cesium' }) });
   const first = await run('analyst_query', {
     layers: ['flights'],
     scope: { kind: 'anywhere' },
@@ -695,7 +696,7 @@ test('an engine switch keeps the last answer for a follow-up on the next engine'
   assert.equal(first.ok, true);
   // The real runner of the outgoing engine is disposed by the switch.
   run.detach();
-  run.attach({ engine: { kind: 'navara' } });
+  run.attach({ engine: createFakeEngine({ kind: 'navara' }) });
   const followUp = await run('analyst_query', {
     layers: ['flights'],
     followUp: true,

src/voice/pointerCrop.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import assert from 'node:assert/strict';
 import test from 'node:test';
 import {
@@ -96,23 +97,16 @@ test('crop: a slow render gets one bounded fresh-frame recovery request', async
   let listener = null;
   try {
     globalThis.document = { hidden: false };
-    const engine = {
+    const engine = createFakeEngine();
-      frames: {
+    engine.frames.postRender.addEventListener = (next) => {
-        postRender: {
+      listener = next;
-          addEventListener(next) {
+      return () => {
-            listener = next;
+        if (listener === next) listener = null;
-            return () => {
+      };
-              if (listener === next) listener = null;
+    };
-            };
+    engine.render.request = () => {
-          },
+      requests += 1;
-        },
+      if (requests === 2) queueMicrotask(() => listener?.());
-      },
-      render: {
-        request() {
-          requests += 1;
-          if (requests === 2) queueMicrotask(() => listener?.());
-        },
-      },
     };
     assert.equal(await renderFreshPointerFrame(engine), true);
     assert.equal(requests, 2, 'only the pointer path retries once');
@@ -127,13 +121,9 @@ test('crop: a hidden document never starts the recovery request', async () => {
   let requests = 0;
   try {
     globalThis.document = { hidden: true };
-    const engine = {
+    const engine = createFakeEngine();
-      frames: { postRender: { addEventListener: () => () => {} } },
+    engine.render.request = () => {
-      render: {
+      requests += 1;
-        request() {
-          requests += 1;
-        },
-      },
     };
     assert.equal(await renderFreshPointerFrame(engine), false);
     assert.equal(requests, 0);

src/voice/sceneRunner.test.mjs

@@ -1,8 +1,9 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import { createSceneRunner, engineSwitchingRefusal } from './sceneRunner.js';
 
-const engine = (kind) => ({ kind });
+const engine = (kind) => createFakeEngine({ kind });
 
 function runnerFor(log) {
   return (scene) => {

src/voice/sceneVoice.test.mjs

@@ -1,3 +1,4 @@
+import { createFakeEngine } from '../globe/testing/fakeEngine.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import { createSceneVoice } from './gevRealtime.js';
@@ -6,11 +7,7 @@ import { createTestVoiceUi } from '../testSupport/voiceUi.mjs';
 function fakeEngine(kind) {
   const canvas = new EventTarget();
   canvas.getBoundingClientRect = () => ({ left: 0, top: 0 });
-  return {
+  return createFakeEngine({ kind, canvas, width: 0, height: 0 });
-    kind,
-    host: { canvas, size: () => ({ width: 0, height: 0 }) },
-    camera: { pose: () => ({}) },
-  };
 }
 
 function fixture() {