Merge remote-tracking branch 'upstream/main' into codex/pr1233-tarktee-cleanup

src/data/cctvVegvesen.test.mjs

@@ -2,11 +2,24 @@ import { test } from 'node:test';
 import assert from 'node:assert/strict';
 
 import {
+  applyVegvesenGroundHeights,
+  clearKartverketHeightCache,
+  fetchKartverketHeights,
+  kartverketBackoffMs,
   loadVegvesenSourcesFromOpenData,
   vegvesenCameraToSource,
 } from '../../server/providers/cctv/sources.js';
 import {
   DEFAULT_VEGVESEN_CCTV_URL,
+  KARTVERKET_HEIGHT_URL,
+  KARTVERKET_CATALOG_WAIT_MS,
+  KARTVERKET_CONCURRENCY,
+  KARTVERKET_FAILURE_BACKOFF_MS,
+  KARTVERKET_MAX_POINTS,
+  KARTVERKET_MAX_RESPONSE_BYTES,
+  KARTVERKET_NULL_TTL_MS,
+  KARTVERKET_USER_AGENT,
+  CCTV_SOURCE_CACHE_MS,
   VEGVESEN_IMAGE_ORIGIN,
 } from '../../server/providers/cctv/constants.js';
 import { createCctvCatalog } from '../../server/providers/cctv/catalog.js';
@@ -104,6 +117,8 @@ test('faulty cameras, off-host frames and bad geometry are dropped', () => {
 });
 
 test('the loader dedupes, and failures degrade to an empty pack', async (t) => {
+  clearKartverketHeightCache();
+  t.after(clearKartverketHeightCache);
   t.mock.method(console, 'log', () => {});
   t.mock.method(console, 'warn', () => {});
   const requested = [];
@@ -127,7 +142,11 @@ test('the loader dedupes, and failures degrade to an empty pack', async (t) => {
     });
   });
   const cameras = await loadVegvesenSourcesFromOpenData();
-  assert.deepEqual(requested, [DEFAULT_VEGVESEN_CCTV_URL]);
+  // The catalog first; the rest is the Kartverket height lookup.
+  assert.equal(requested[0], DEFAULT_VEGVESEN_CCTV_URL);
+  // Two unique positions: one Kartverket request.
+  assert.equal(requested.length, 2);
+  assert.ok(requested[1].startsWith(KARTVERKET_HEIGHT_URL));
   // Nearest-to-anchor first: Oslo leads.
   assert.deepEqual(
     cameras.map((c) => c.id),
@@ -200,3 +219,604 @@ test('CCTV_VEGVESEN_ENABLED=0 keeps the lane from being loaded', async (t) => {
     );
   });
 });
+
+/** Answer a Kartverket request the way the live API does: echo every point,
+ * with the height `heightFor(x, y)` returns (null = outside coverage). */
+const kartverketResponse = (url, heightFor) => {
+  const points = JSON.parse(new URL(url).searchParams.get('punkter'));
+  return Response.json({
+    koordsys: 4258,
+    punkter: points.map(([x, y]) => ({ x, y, z: heightFor(x, y) })),
+  });
+};
+
+/** Cameras at distinct Norwegian positions. */
+const cameraAt = (i) => ({
+  id: `no-vegvesen-${i}`,
+  lat: 60 + i * 0.001,
+  lon: 7 + i * 0.001,
+  groundElevationM: 150,
+});
+
+const withHeightsEnv = (t) => {
+  const saved = process.env.CCTV_VEGVESEN_HEIGHTS;
+  delete process.env.CCTV_VEGVESEN_HEIGHTS;
+  clearKartverketHeightCache();
+  t.after(() => {
+    clearKartverketHeightCache();
+    if (saved === undefined) delete process.env.CCTV_VEGVESEN_HEIGHTS;
+    else process.env.CCTV_VEGVESEN_HEIGHTS = saved;
+  });
+  t.mock.method(console, 'log', () => {});
+  t.mock.method(console, 'warn', () => {});
+};
+
+const sentPoints = (url) =>
+  JSON.parse(new URL(url).searchParams.get('punkter'));
+
+test('Kartverket heights come in batches of 20, matched by echoed coordinates', async (t) => {
+  withHeightsEnv(t);
+  const requested = [];
+  t.mock.method(globalThis, 'fetch', async (url, init) => {
+    requested.push(String(url));
+    assert.ok(String(url).startsWith(KARTVERKET_HEIGHT_URL));
+    assert.equal(init.headers['User-Agent'], KARTVERKET_USER_AGENT);
+    // Redirects are refused, so a request can never leave the fixed host.
+    assert.equal(init.redirect, 'error');
+    // Reply in reverse order: matching must not depend on list position.
+    const response = kartverketResponse(url, (x) =>
+      x > 7.04 ? null : Math.round((x - 7) * 10000),
+    );
+    const body = await response.json();
+    body.punkter.reverse();
+    return Response.json(body);
+  });
+  const { heights, failure } = await fetchKartverketHeights(
+    Array.from({ length: 50 }, (_, i) => cameraAt(i)),
+  );
+  assert.equal(failure, null);
+  // One pass, no retries: 20 + 20 + 10.
+  assert.deepEqual(
+    requested.map((url) => sentPoints(url).length),
+    [KARTVERKET_MAX_POINTS, 20, 10],
+  );
+  for (const url of requested) {
+    assert.equal(new URL(url).searchParams.get('koordsys'), '4258');
+  }
+  assert.equal(heights.size, 50);
+  assert.equal(heights.get('7.010000,60.010000'), 100);
+  // Past x = 7.04 the API has no height: recorded as null, never as 0.
+  assert.equal(heights.get('7.049000,60.049000'), null);
+});
+
+test('only the points a request asked about are recorded', async (t) => {
+  withHeightsEnv(t);
+  t.mock.method(globalThis, 'fetch', async (url) => {
+    const points = sentPoints(url);
+    return Response.json({
+      koordsys: 4258,
+      punkter: [
+        ...points.map(([x, y]) => ({ x, y, z: 10 })),
+        { x: 7.5, y: 60.5, z: 999 }, // never asked
+      ],
+    });
+  });
+  const { heights } = await fetchKartverketHeights([cameraAt(0)]);
+  assert.deepEqual([...heights.entries()], [['7.000000,60.000000', 10]]);
+});
+
+test('either water marker counts as the surface', async (t) => {
+  withHeightsEnv(t);
+  t.mock.method(globalThis, 'fetch', async (url) => {
+    const [a, b, c] = sentPoints(url);
+    return Response.json({
+      koordsys: 4258,
+      punkter: [
+        {
+          x: a[0],
+          y: a[1],
+          z: -547.1,
+          datakilde: 'dybdekurver',
+          terreng: null,
+        },
+        { x: b[0], y: b[1], z: -9.2, datakilde: 'dtm1', terreng: 'Havflate' },
+        {
+          x: c[0],
+          y: c[1],
+          z: -0.2,
+          datakilde: 'dtm1',
+          terreng: 'ÅpentOmråde',
+        },
+      ],
+    });
+  });
+  const { heights } = await fetchKartverketHeights([
+    cameraAt(0),
+    cameraAt(1),
+    cameraAt(2),
+  ]);
+  assert.equal(heights.get('7.000000,60.000000'), 0);
+  assert.equal(heights.get('7.001000,60.001000'), 0);
+  // A quay just below the datum on land data stays as measured.
+  assert.equal(heights.get('7.002000,60.002000'), -0.2);
+});
+
+test('heights outside -20..2500 m and points outside Norway are not used', async (t) => {
+  withHeightsEnv(t);
+  const requested = [];
+  t.mock.method(globalThis, 'fetch', async (url) => {
+    requested.push(String(url));
+    const zs = [-20, -20.5, 2500, 2500.5];
+    const points = sentPoints(url);
+    return Response.json({
+      koordsys: 4258,
+      punkter: points.map(([x, y], i) => ({ x, y, z: zs[i] })),
+    });
+  });
+  const { heights } = await fetchKartverketHeights([
+    cameraAt(0),
+    cameraAt(1),
+    cameraAt(2),
+    cameraAt(3),
+    { lat: 55.68, lon: 12.57 }, // Copenhagen: never sent
+  ]);
+  assert.equal(requested.length, 1);
+  assert.equal(sentPoints(requested[0]).length, 4);
+  assert.deepEqual(
+    [0, 1, 2, 3].map((i) =>
+      heights.get(
+        `${(7 + i * 0.001).toFixed(6)},${(60 + i * 0.001).toFixed(6)}`,
+      ),
+    ),
+    [-20, null, 2500, null],
+  );
+});
+
+test('no more than eight requests are in flight', async (t) => {
+  withHeightsEnv(t);
+  let inFlight = 0;
+  let peak = 0;
+  t.mock.method(globalThis, 'fetch', async (url) => {
+    inFlight += 1;
+    peak = Math.max(peak, inFlight);
+    await new Promise((resolve) => setTimeout(resolve, 5));
+    inFlight -= 1;
+    return kartverketResponse(url, () => 1);
+  });
+  const { heights } = await fetchKartverketHeights(
+    Array.from({ length: 400 }, (_, i) => cameraAt(i)),
+  );
+  assert.equal(heights.size, 400);
+  assert.equal(peak, KARTVERKET_CONCURRENCY);
+});
+
+test('a transport failure stops the lookup: no retries, no new requests', async (t) => {
+  withHeightsEnv(t);
+  let calls = 0;
+  t.mock.method(globalThis, 'fetch', async () => {
+    calls += 1;
+    return new Response('busy', {
+      status: 429,
+      headers: { 'Retry-After': '120' },
+    });
+  });
+  const { heights, failure } = await fetchKartverketHeights(
+    Array.from({ length: 400 }, (_, i) => cameraAt(i)),
+  );
+  // The first wave is already in flight when the first failure lands; nothing
+  // after it starts, and no point is resent.
+  assert.equal(calls, KARTVERKET_CONCURRENCY);
+  assert.equal(heights.size, 0);
+  assert.deepEqual(failure, {
+    status: 429,
+    retryAfter: '120',
+    deadline: false,
+  });
+});
+
+/** A fetch that never answers, and rejects only when its signal aborts. */
+const hangingFetch = (url, init) => {
+  assert.ok(init.signal instanceof AbortSignal);
+  return new Promise((_, reject) => {
+    init.signal.addEventListener('abort', () => reject(init.signal.reason));
+  });
+};
+
+test('the lookup deadline bounds a hanging service', async (t) => {
+  withHeightsEnv(t);
+  t.mock.method(globalThis, 'fetch', hangingFetch);
+  const started = Date.now();
+  const { heights, failure } = await fetchKartverketHeights([cameraAt(0)], {
+    timeoutMs: 30,
+  });
+  const elapsed = Date.now() - started;
+  assert.ok(elapsed >= 25 && elapsed < 2000, `elapsed ${elapsed} ms`);
+  assert.equal(heights.size, 0);
+  assert.deepEqual(failure, { status: null, retryAfter: null, deadline: true });
+});
+
+test('one hanging request times out on its own, as a failing service', async (t) => {
+  withHeightsEnv(t);
+  t.mock.method(globalThis, 'fetch', hangingFetch);
+  const { failure } = await fetchKartverketHeights([cameraAt(0)], {
+    timeoutMs: 60_000,
+    requestTimeoutMs: 20,
+  });
+  assert.deepEqual(failure, {
+    status: null,
+    retryAfter: null,
+    deadline: false,
+  });
+});
+
+test('the deadline is shared: later requests do not get a fresh one', async (t) => {
+  withHeightsEnv(t);
+  let calls = 0;
+  t.mock.method(globalThis, 'fetch', (url, init) => {
+    calls += 1;
+    return new Promise((resolve, reject) => {
+      const timer = setTimeout(
+        () => resolve(kartverketResponse(url, () => 1)),
+        40,
+      );
+      init.signal.addEventListener('abort', () => {
+        clearTimeout(timer);
+        reject(init.signal.reason);
+      });
+    });
+  });
+  // Five waves of 40 ms against a 100 ms deadline for the whole lookup.
+  const { heights, failure } = await fetchKartverketHeights(
+    Array.from({ length: 5 * KARTVERKET_CONCURRENCY * 20 }, (_, i) =>
+      cameraAt(i),
+    ),
+    { timeoutMs: 100 },
+  );
+  assert.equal(failure?.deadline, true);
+  assert.ok(heights.size < 5 * KARTVERKET_CONCURRENCY * 20);
+  assert.ok(calls < 5 * KARTVERKET_CONCURRENCY, `calls ${calls}`);
+});
+
+test('a 503, an unreadable or an oversized body stops the lookup', async (t) => {
+  withHeightsEnv(t);
+  const answers = {
+    503: () => new Response('down', { status: 503 }),
+    'not json': () =>
+      new Response('<html>maintenance</html>', {
+        headers: { 'Content-Type': 'text/html' },
+      }),
+    oversized: () =>
+      Response.json({
+        punkter: [],
+        pad: 'x'.repeat(KARTVERKET_MAX_RESPONSE_BYTES + 1),
+      }),
+  };
+  for (const [label, answer] of Object.entries(answers)) {
+    clearKartverketHeightCache();
+    let calls = 0;
+    t.mock.method(globalThis, 'fetch', async () => {
+      calls += 1;
+      return answer();
+    });
+    const { heights, failure } = await fetchKartverketHeights(
+      Array.from({ length: 400 }, (_, i) => cameraAt(i)),
+    );
+    assert.equal(calls, KARTVERKET_CONCURRENCY, label);
+    assert.equal(heights.size, 0, label);
+    assert.equal(failure?.deadline, false, label);
+    assert.equal(failure?.status, label === '503' ? 503 : null, label);
+  }
+});
+
+test('a 4xx rejects that request only: its points get no height, the rest go on', async (t) => {
+  withHeightsEnv(t);
+  t.mock.method(globalThis, 'fetch', async (url) =>
+    sentPoints(url)[0][0] === 7
+      ? new Response('bad point', { status: 400 })
+      : kartverketResponse(url, () => 42),
+  );
+  const { heights, failure } = await fetchKartverketHeights(
+    Array.from({ length: 40 }, (_, i) => cameraAt(i)),
+  );
+  assert.equal(failure, null);
+  assert.equal(heights.size, 40);
+  assert.equal(heights.get('7.000000,60.000000'), null);
+  assert.equal(heights.get('7.020000,60.020000'), 42);
+});
+
+test('a point a 200 answer leaves out is cached as no height', async (t) => {
+  withHeightsEnv(t);
+  const fetchMock = t.mock.method(globalThis, 'fetch', async (url) => {
+    const points = sentPoints(url).slice(1); // drop the first point
+    return Response.json({
+      koordsys: 4258,
+      punkter: points.map(([x, y]) => ({ x, y, z: 7 })),
+    });
+  });
+  const cameras = [cameraAt(0), cameraAt(1)];
+  assert.equal(await applyVegvesenGroundHeights(cameras), 1);
+  assert.equal(cameras[0].groundElevationM, 150);
+  // The next refresh asks nothing: the left-out point is a cached miss.
+  assert.equal(await applyVegvesenGroundHeights([cameraAt(0), cameraAt(1)]), 1);
+  assert.equal(fetchMock.mock.callCount(), 1);
+});
+
+test('Retry-After sets the backoff, bounded to [1 min, 1 h]', () => {
+  const now = Date.parse('2026-10-06T12:00:00Z');
+  assert.equal(kartverketBackoffMs('120', now), 120_000);
+  assert.equal(kartverketBackoffMs('5', now), 60_000);
+  assert.equal(kartverketBackoffMs('86400', now), 3_600_000);
+  assert.equal(
+    kartverketBackoffMs('Mon, 06 Oct 2026 12:05:00 GMT', now),
+    300_000,
+  );
+  assert.equal(kartverketBackoffMs(null, now), KARTVERKET_FAILURE_BACKOFF_MS);
+  assert.equal(kartverketBackoffMs('soon', now), KARTVERKET_FAILURE_BACKOFF_MS);
+});
+
+test('heights are cached, and misses are not asked again until they expire', async (t) => {
+  withHeightsEnv(t);
+  let clock = 1_000_000;
+  const now = () => clock;
+  const asked = [];
+  t.mock.method(globalThis, 'fetch', async (url) => {
+    asked.push(sentPoints(url).length);
+    return kartverketResponse(url, (x) => (x < 7.002 ? 1043.26 : null));
+  });
+  const cameras = [cameraAt(0), cameraAt(1), cameraAt(5)];
+  assert.equal(await applyVegvesenGroundHeights(cameras, { now }), 2);
+  assert.deepEqual(
+    cameras.map((c) => c.groundElevationM),
+    [1043.3, 1043.3, 150],
+  );
+  // The next refresh asks nothing: heights and the miss are both cached.
+  assert.equal(
+    await applyVegvesenGroundHeights([cameraAt(0), cameraAt(1), cameraAt(5)], {
+      now,
+    }),
+    2,
+  );
+  assert.deepEqual(asked, [3]);
+  // Once the miss expires, only that point is asked again.
+  clock += KARTVERKET_NULL_TTL_MS + 1;
+  await applyVegvesenGroundHeights([cameraAt(0), cameraAt(5)], { now });
+  assert.deepEqual(asked, [3, 1]);
+});
+
+test('after a failure no lookup starts until the backoff ends', async (t) => {
+  withHeightsEnv(t);
+  let clock = 1_000_000;
+  const now = () => clock;
+  const fetchMock = t.mock.method(globalThis, 'fetch', async () => {
+    throw new Error('offline');
+  });
+  const cameras = [cameraAt(0)];
+  assert.equal(await applyVegvesenGroundHeights(cameras, { now }), 0);
+  assert.equal(cameras[0].groundElevationM, 150);
+  assert.equal(fetchMock.mock.callCount(), 1);
+
+  // The default backoff outlasts the catalog refresh, so the next refresh
+  // and every one inside the backoff cost nothing.
+  assert.ok(KARTVERKET_FAILURE_BACKOFF_MS > CCTV_SOURCE_CACHE_MS);
+  clock += CCTV_SOURCE_CACHE_MS;
+  assert.equal(await applyVegvesenGroundHeights([cameraAt(0)], { now }), 0);
+  clock += KARTVERKET_FAILURE_BACKOFF_MS - CCTV_SOURCE_CACHE_MS - 1;
+  assert.equal(await applyVegvesenGroundHeights([cameraAt(0)], { now }), 0);
+  assert.equal(fetchMock.mock.callCount(), 1);
+
+  // After it, the failed point is asked again.
+  clock += 2;
+  fetchMock.mock.mockImplementation(async (url) =>
+    kartverketResponse(url, () => 321),
+  );
+  const later = [cameraAt(0)];
+  assert.equal(await applyVegvesenGroundHeights(later, { now }), 1);
+  assert.equal(later[0].groundElevationM, 321);
+  assert.equal(fetchMock.mock.callCount(), 2);
+});
+
+test('a 429 backs off for its Retry-After, not the default', async (t) => {
+  withHeightsEnv(t);
+  let clock = 1_000_000;
+  const now = () => clock;
+  const retryAfterS = 50 * 60;
+  const fetchMock = t.mock.method(
+    globalThis,
+    'fetch',
+    async () =>
+      new Response('busy', {
+        status: 429,
+        headers: { 'Retry-After': String(retryAfterS) },
+      }),
+  );
+  await applyVegvesenGroundHeights([cameraAt(0)], { now });
+  assert.equal(fetchMock.mock.callCount(), 1);
+  clock += KARTVERKET_FAILURE_BACKOFF_MS + 1;
+  await applyVegvesenGroundHeights([cameraAt(0)], { now });
+  assert.equal(fetchMock.mock.callCount(), 1);
+  clock += retryAfterS * 1000 - KARTVERKET_FAILURE_BACKOFF_MS;
+  await applyVegvesenGroundHeights([cameraAt(0)], { now });
+  assert.equal(fetchMock.mock.callCount(), 2);
+});
+
+test('a lookup cut short by its deadline resumes on the next refresh', async (t) => {
+  withHeightsEnv(t);
+  let clock = 1_000_000;
+  const now = () => clock;
+  t.mock.method(globalThis, 'fetch', hangingFetch);
+  // The lookup runs out of time; that is not a failing service.
+  assert.equal(
+    await applyVegvesenGroundHeights([cameraAt(0)], {
+      now,
+      timeoutMs: 10,
+      waitMs: 1000,
+    }),
+    0,
+  );
+  const fetchMock = t.mock.method(globalThis, 'fetch', async (url) =>
+    kartverketResponse(url, () => 64),
+  );
+  clock += CCTV_SOURCE_CACHE_MS;
+  const cameras = [cameraAt(0)];
+  assert.equal(await applyVegvesenGroundHeights(cameras, { now }), 1);
+  assert.equal(cameras[0].groundElevationM, 64);
+  assert.equal(fetchMock.mock.callCount(), 1);
+});
+
+test('overlapping refreshes share one lookup', async (t) => {
+  withHeightsEnv(t);
+  let release;
+  const gate = new Promise((resolve) => {
+    release = resolve;
+  });
+  const fetchMock = t.mock.method(globalThis, 'fetch', async (url) => {
+    await gate;
+    return kartverketResponse(url, () => 3);
+  });
+  await Promise.all([
+    applyVegvesenGroundHeights([cameraAt(0)], { waitMs: 5 }),
+    applyVegvesenGroundHeights([cameraAt(0)], { waitMs: 5 }),
+  ]);
+  assert.equal(fetchMock.mock.callCount(), 1);
+  release();
+});
+
+test('a warm cache does not wait for a few new cameras', async (t) => {
+  withHeightsEnv(t);
+  const cameras = Array.from({ length: 20 }, (_, i) => cameraAt(i));
+  t.mock.method(globalThis, 'fetch', async (url) =>
+    kartverketResponse(url, () => 500),
+  );
+  assert.equal(await applyVegvesenGroundHeights(cameras), 20);
+  let release;
+  const gate = new Promise((resolve) => {
+    release = resolve;
+  });
+  const fetchMock = t.mock.method(globalThis, 'fetch', async (url) => {
+    await gate;
+    return kartverketResponse(url, () => 600);
+  });
+  const refresh = [...cameras, cameraAt(20)];
+  const started = Date.now();
+  assert.equal(
+    await applyVegvesenGroundHeights(refresh, { waitMs: 5_000 }),
+    20,
+  );
+  assert.ok(Date.now() - started < 1000);
+  assert.equal(fetchMock.mock.callCount(), 1);
+  // The background lookup fills the cache for the next refresh.
+  release();
+  await new Promise((resolve) => setTimeout(resolve, 20));
+  const next = [...cameras, cameraAt(20)];
+  assert.equal(await applyVegvesenGroundHeights(next), 21);
+  assert.equal(next[20].groundElevationM, 600);
+});
+
+test('cameras without numeric coordinates are skipped, never thrown on', async (t) => {
+  withHeightsEnv(t);
+  t.mock.method(globalThis, 'fetch', async (url) =>
+    kartverketResponse(url, () => 9),
+  );
+  const cameras = [
+    { id: 'no-coordinates' },
+    null,
+    { id: 'strings', lat: '60', lon: '7' },
+    cameraAt(0),
+  ];
+  assert.equal(await applyVegvesenGroundHeights(cameras), 1);
+  assert.equal(cameras[3].groundElevationM, 9);
+});
+
+test('a lookup started before a cache clear cannot write after it', async (t) => {
+  withHeightsEnv(t);
+  let release;
+  const gate = new Promise((resolve) => {
+    release = resolve;
+  });
+  t.mock.method(globalThis, 'fetch', async (url) => {
+    await gate;
+    return kartverketResponse(url, () => 111);
+  });
+  await applyVegvesenGroundHeights([cameraAt(0)], { waitMs: 5 });
+  clearKartverketHeightCache();
+  t.mock.method(globalThis, 'fetch', async (url) =>
+    kartverketResponse(url, () => 222),
+  );
+  const fresh = [cameraAt(0)];
+  assert.equal(await applyVegvesenGroundHeights(fresh), 1);
+  assert.equal(fresh[0].groundElevationM, 222);
+  release();
+  await new Promise((resolve) => setTimeout(resolve, 20));
+  const later = [cameraAt(0)];
+  await applyVegvesenGroundHeights(later, { waitMs: 0 });
+  assert.equal(later[0].groundElevationM, 222);
+});
+
+test('CCTV_VEGVESEN_HEIGHTS=0 skips the lookup', async (t) => {
+  withHeightsEnv(t);
+  const fetchMock = t.mock.method(globalThis, 'fetch', async (url) =>
+    kartverketResponse(url, () => 5),
+  );
+  process.env.CCTV_VEGVESEN_HEIGHTS = '0';
+  const cameras = [cameraAt(0)];
+  assert.equal(await applyVegvesenGroundHeights(cameras), 0);
+  assert.equal(cameras[0].groundElevationM, 150);
+  assert.equal(fetchMock.mock.callCount(), 0);
+});
+
+test('a slow lookup does not hold the catalog; the next refresh applies it', async (t) => {
+  withHeightsEnv(t);
+  let release;
+  const gate = new Promise((resolve) => {
+    release = resolve;
+  });
+  t.mock.method(globalThis, 'fetch', async (url) => {
+    await gate;
+    return kartverketResponse(url, () => 812);
+  });
+  const first = [cameraAt(0)];
+  assert.equal(await applyVegvesenGroundHeights(first, { waitMs: 20 }), 0);
+  assert.equal(first[0].groundElevationM, 150);
+  release();
+  // The lookup kept running and filled the cache for the next refresh.
+  await new Promise((resolve) => setTimeout(resolve, 20));
+  const next = [cameraAt(0)];
+  assert.equal(await applyVegvesenGroundHeights(next, { waitMs: 20 }), 1);
+  assert.equal(next[0].groundElevationM, 812);
+});
+
+test('the loader applies Kartverket heights to the cameras it returns', async (t) => {
+  withHeightsEnv(t);
+  t.mock.method(globalThis, 'fetch', async (url) => {
+    if (String(url).startsWith(KARTVERKET_HEIGHT_URL)) {
+      return kartverketResponse(url, () => 987.6);
+    }
+    return Response.json({ type: 'FeatureCollection', features: [feature()] });
+  });
+  const cameras = await loadVegvesenSourcesFromOpenData();
+  assert.deepEqual(
+    cameras.map((c) => [c.id, c.groundElevationM]),
+    [['no-vegvesen-3000063_1', 987.6]],
+  );
+});
+
+test('the loader budgets the height wait from its own start', async (t) => {
+  withHeightsEnv(t);
+  const realNow = Date.now.bind(Date);
+  let offset = 0;
+  t.mock.method(Date, 'now', () => realNow() + offset);
+  t.mock.method(globalThis, 'fetch', (url, init) => {
+    if (String(url).startsWith(KARTVERKET_HEIGHT_URL)) {
+      return hangingFetch(url, init);
+    }
+    // The catalog fetch uses up all but 10 ms of the lane's budget.
+    offset += KARTVERKET_CATALOG_WAIT_MS - 10;
+    return Promise.resolve(
+      Response.json({ type: 'FeatureCollection', features: [feature()] }),
+    );
+  });
+  const started = performance.now();
+  const cameras = await loadVegvesenSourcesFromOpenData();
+  assert.ok(performance.now() - started < 1000);
+  assert.equal(cameras[0].groundElevationM, 150);
+});

src/data/dataCredits.js

@@ -293,7 +293,10 @@ export const DATA_CREDITS = [
     html:
       'Road cameras (Norway): contains data under the ' +
       '<a href="https://data.norge.no/nlod/en/2.0" target="_blank" rel="noopener">Norwegian licence for Open Government data (NLOD)</a> ' +
-      'distributed by Statens vegvesen',
+      'distributed by Statens vegvesen · camera ground heights © ' +
+      '<a href="https://kartverket.no/en/api-and-data/terrengdata" target="_blank" rel="noopener">Kartverket</a> ' +
+      '(<a href="https://creativecommons.org/licenses/by/4.0/" target="_blank" rel="noopener">CC BY 4.0</a>); ' +
+      'modified: heights over water set to 0 m and rounded to 0.1 m',
   },
   {
     key: 'nyc-cctv',