test: keep media oracles optional in clean clones

Author: OmarMusayev

test/test-gif-decode.ts

@@ -958,8 +958,10 @@ test("decodeGifFirstFrame agrees byte-for-byte with frames[0] (synthetic)", () =
   );
 });
 
-test("decodeGifFirstFrame agrees with the full decode on both fixture GIFs", () => {
-  for (const path of [TESTSRC_GIF, SINTEL_GIF]) {
+test("decodeGifFirstFrame agrees with the full decode on every available fixture GIF", () => {
+  const fixtures = [TESTSRC_GIF, SINTEL_GIF].filter(existsSync);
+  assert(fixtures.length > 0, "at least the checked-in fixture is present");
+  for (const path of fixtures) {
     const bytes = new Uint8Array(readFileSync(path));
     const full = mustDecode(bytes, path);
     const first = decodeGifFirstFrame(bytes);
@@ -1090,7 +1092,11 @@ if (FFMPEG_DIR === null) {
   const fixtures: Array<[string, string, number]> = [
     [TESTSRC_GIF, "testsrc-48x32-8f", 8],
     [SINTEL_GIF, "sintel-3s", 36],
-  ];
+  ].filter(([path]) => existsSync(path));
+
+  if (!existsSync(SINTEL_GIF)) {
+    console.log("  \x1b[33m- skipped: optional devnotes/media/sintel-3s.gif fixture missing\x1b[0m");
+  }
 
   for (const [path, label, expectedFrames] of fixtures) {
     test(`${label}: frames match ffmpeg's composited output (MAE ~0)`, () => {
@@ -1151,22 +1157,24 @@ if (FFMPEG_DIR === null) {
     }
   });
 
-  test("sintel-3s: first-frame fast path is cheaper than the full decode", () => {
-    const bytes = new Uint8Array(readFileSync(SINTEL_GIF));
-    const t0 = performance.now();
-    const full = decodeGif(bytes);
-    const fullMs = performance.now() - t0;
-    const t1 = performance.now();
-    const first = decodeGifFirstFrame(bytes);
-    const firstMs = performance.now() - t1;
-    assert(full.ok && first !== null, "both paths decode");
-    measurements.push(`sintel-3s: full decode ${fullMs.toFixed(1)} ms, first frame only ${firstMs.toFixed(1)} ms`);
-    console.log(`    ${measurements[measurements.length - 1]}`);
-    // Frame 0 is ~1/36th of the LZW work; anything close to the full decode
-    // would mean the early-out is not early. Generous 0.75 bound so timer
-    // noise on a loaded machine cannot flake the suite.
-    assert(firstMs < fullMs * 0.75 + 2, `first-frame ${firstMs} ms vs full ${fullMs} ms`);
-  });
+  if (existsSync(SINTEL_GIF)) {
+    test("sintel-3s: first-frame fast path is cheaper than the full decode", () => {
+      const bytes = new Uint8Array(readFileSync(SINTEL_GIF));
+      const t0 = performance.now();
+      const full = decodeGif(bytes);
+      const fullMs = performance.now() - t0;
+      const t1 = performance.now();
+      const first = decodeGifFirstFrame(bytes);
+      const firstMs = performance.now() - t1;
+      assert(full.ok && first !== null, "both paths decode");
+      measurements.push(`sintel-3s: full decode ${fullMs.toFixed(1)} ms, first frame only ${firstMs.toFixed(1)} ms`);
+      console.log(`    ${measurements[measurements.length - 1]}`);
+      // Frame 0 is ~1/36th of the LZW work; anything close to the full decode
+      // would mean the early-out is not early. Generous 0.75 bound so timer
+      // noise on a loaded machine cannot flake the suite.
+      assert(firstMs < fullMs * 0.75 + 2, `first-frame ${firstMs} ms vs full ${fullMs} ms`);
+    });
+  }
 }
 
 // ═════════════════════════════════════════════════════════

test/test-video-pack-format.ts

@@ -81,7 +81,6 @@ function errText(err: unknown): string {
 
 const HERE = dirname(fileURLToPath(import.meta.url));
 const REAL_JPEG = join(HERE, "fixtures", "quarters-64x48.jpg");
-const TRAILER = join(HERE, "..", "devnotes", "media", "sintel-trailer.mp4");
 
 // ─── Synthetic frames ─────────────────────────────────────
 
@@ -744,9 +743,16 @@ test("sha1File matches shasum(1) on a small file", () => {
 });
 
 test("sha1File hashes a file larger than its 1 MiB read chunk correctly", () => {
-  // 4.4 MB, so the chunk loop runs five times — the case a single-read
-  // implementation would silently get wrong.
-  assertEqual(sha1File(TRAILER), "9b678890fb8ca401c28e7ca09171ec008a154b97", "sintel-trailer.mp4");
+  // One chunk plus 17 bytes forces a second read. The digest was pinned with
+  // `head -c 1048593 /dev/zero | tr '\\0' a | shasum -a 1`.
+  const dir = mkdtempSync(join(tmpdir(), "tvf-sha1-large-"));
+  try {
+    const path = join(dir, "large.bin");
+    writeFileSync(path, Buffer.alloc(1024 * 1024 + 17, 0x61));
+    assertEqual(sha1File(path), "4d936f3b48d0ec41dc5a43693850fe1fe7b5f9f1", "large synthetic file");
+  } finally {
+    rmSync(dir, { recursive: true, force: true });
+  }
 });
 
 test("sha1File returns \"\" for an unreadable source instead of throwing", () => {
@@ -811,7 +817,10 @@ test("A pack carries the source digest for staleness detection", () => {
     "digest",
   );
   assertEqual(pack.header.sourceSha1, digest, "digest survives the roundtrip");
-  assert(pack.header.sourceSha1 !== sha1File(TRAILER), "and a different source would not match");
+  assert(
+    pack.header.sourceSha1 !== sha1File(join(HERE, "fixtures", "video", "testsrc-48x32-8f.gif")),
+    "and a different source would not match",
+  );
 });
 
 // ═════════════════════════════════════════════════════════════
@@ -837,7 +846,7 @@ for (let i = 0; i < BIG_COUNT; i++) {
 
 const t0 = performance.now();
 const bigBytes = encodePack(
-  { width: 854, height: 480, fps: 24, frameCount: BIG_COUNT, durationMs: (BIG_COUNT * 1000) / 24, sourceSha1: sha1File(TRAILER) },
+  { width: 854, height: 480, fps: 24, frameCount: BIG_COUNT, durationMs: (BIG_COUNT * 1000) / 24, sourceSha1: sha1File(REAL_JPEG) },
   bigFrames,
 );
 const encodeMs = performance.now() - t0;