Pin that an empty installation answer is never reported as an unavailable source

src/layers/installations/edgeCases.test.mjs

@@ -0,0 +1,86 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { installationFeedback } from '../../data/installationFeedback.js';
+import { createInstallationSource } from './source.js';
+
+const box = { south: 30.1, west: -97.9, north: 30.3, east: -97.6 };
+
+/** What the panel says after one request: a count, or the failure reason. */
+async function feedbackFor(source) {
+  try {
+    const payload = await source.getMappedSites(box);
+    return {
+      outcome: 'ready',
+      text: installationFeedback({
+        status: payload.status,
+        count: payload.records.length,
+      }),
+    };
+  } catch (error) {
+    return {
+      outcome: 'unavailable',
+      text: installationFeedback({
+        status: 'unavailable',
+        failureReason: error.failureReason,
+      }),
+    };
+  }
+}
+
+test('edge:military-installations: an empty Overpass answer is not an unavailable source', async () => {
+  const empty = createInstallationSource({
+    fetchImpl: async () => Response.json({ elements: [], status: 'ready' }),
+  });
+  assert.deepEqual(await feedbackFor(empty), {
+    outcome: 'ready',
+    text: 'No mapped sites in view',
+  });
+
+  const failing = createInstallationSource({
+    fetchImpl: async () =>
+      Response.json({ reason: 'timeout' }, { status: 504 }),
+  });
+  assert.deepEqual(await feedbackFor(failing), {
+    outcome: 'unavailable',
+    text: 'Overpass timed out',
+  });
+
+  const offline = createInstallationSource({
+    fetchImpl: async () => {
+      throw new TypeError('Failed to fetch');
+    },
+  });
+  assert.equal((await feedbackFor(offline)).outcome, 'unavailable');
+});
+
+test('edge:military-installations: empty tiles and unavailable tiles stay distinct on the tile fallback', async () => {
+  const notConfigured = async () =>
+    Response.json({ code: 'OVERPASS_NOT_CONFIGURED' }, { status: 503 });
+  const emptyTiles = createInstallationSource({
+    fetchImpl: notConfigured,
+    loadNames: async () => [],
+    mapTiles: {
+      fetchBounds: async () => ({ tiles: [{ military: [] }], partial: false }),
+      clear() {},
+    },
+  });
+  assert.deepEqual(await feedbackFor(emptyTiles), {
+    outcome: 'ready',
+    text: 'No mapped sites in view',
+  });
+
+  const downTiles = createInstallationSource({
+    fetchImpl: notConfigured,
+    loadNames: async () => [],
+    mapTiles: {
+      fetchBounds: async () => {
+        throw new Error('HTTP 502');
+      },
+      clear() {},
+    },
+  });
+  assert.deepEqual(await feedbackFor(downTiles), {
+    outcome: 'unavailable',
+    text: 'Map tiles temporarily unavailable',
+  });
+});