fix(auto-thumbnail): [PKG-AUTO-THUMB-07] release terminal canvas storage

test/auto-thumbnail-canvas.test.js

@@ -0,0 +1,102 @@
+import assert from 'node:assert/strict'
+// eslint-disable-next-line test/no-import-node-test -- Repository canvas resource ownership regressions.
+import test from 'node:test'
+import { autoThumbnailCandidate, autoThumbnailEnvironment } from './helpers/auto-thumbnail.js'
+
+const implementation = await autoThumbnailCandidate()
+async function setup(number = 2) {
+  const env = autoThumbnailEnvironment(implementation)
+  await env.factory({ width: 80, number })(env.art)
+  env.art.emit('video:loadedmetadata')
+  return env
+}
+
+for (const event of ['destroy', 'restart']) {
+  test(`Auto-thumbnail clears a retained canvas when ${event} cancels an encoding`, async () => {
+    const env = await setup()
+    env.metadata()
+    env.seeked()
+    const canvas = env.canvases[0]
+    assert.equal(canvas.width * canvas.height, 36000)
+    env.art.emit(event)
+    assert.deepEqual([canvas.width, canvas.height], [0, 0])
+    env.finish()
+    assert.equal(env.updates.length, 0)
+    assert.equal(env.urls.size, 0)
+    assert.equal(env.attached.size, 0)
+    if (event === 'restart') {
+      env.art.emit('video:loadedmetadata')
+      env.metadata()
+      assert.deepEqual([env.canvases[1].width, env.canvases[1].height], [800, 45])
+      assert.deepEqual([canvas.width, canvas.height], [0, 0])
+    }
+    env.art.emit('destroy')
+  })
+}
+
+test('Auto-thumbnail clears completed canvas storage while retaining the encoded preview', async () => {
+  const env = await setup(1)
+  env.metadata()
+  env.seeked()
+  const blob = { type: 'image/jpeg', content: 'encoded image owns its bytes' }
+  env.finish(0, blob)
+  assert.deepEqual([env.canvases[0].width, env.canvases[0].height], [0, 0])
+  assert.equal(env.urls.get(env.art.thumbnails.url), blob)
+  assert.equal(env.attached.size, 0)
+  env.art.emit('destroy')
+  assert.equal(env.urls.size, 0)
+})
+
+test('Auto-thumbnail clears allocated dimensions if context creation fails', async () => {
+  const env = await setup()
+  env.controls.nullContext = true
+  env.metadata()
+  assert.deepEqual([env.canvases[0].width, env.canvases[0].height], [0, 0])
+  assert.equal(env.warnings.length, 1)
+  assert.equal(env.attached.size, 0)
+  env.art.emit('destroy')
+})
+
+test('Auto-thumbnail still clears height and decoder if the width reset throws', async () => {
+  const env = await setup()
+  env.metadata()
+  const canvas = env.canvases[0]
+  const failure = new Error('Width reset failed')
+  Object.defineProperty(canvas, 'width', {
+    get: () => 800,
+    set() {
+      throw failure
+    },
+  })
+  env.art.emit('destroy')
+  assert.equal(canvas.height, 0)
+  assert.equal(env.attached.size, 0)
+  assert.equal(env.videos[0].src, undefined)
+  assert.equal(env.timers.size, 0)
+  assert.equal(env.warnings.length, 1)
+  assert.equal(env.warnings[0][1], failure)
+})
+
+test('Auto-thumbnail does not allocate height after a width setter closes the job', async () => {
+  const env = await setup()
+  const createElement = env.box.document.createElement
+  env.box.document.createElement = function (name) {
+    const element = createElement.call(this, name)
+    if (name === 'canvas') {
+      let width = 0
+      Object.defineProperty(element, 'width', {
+        get: () => width,
+        set(value) {
+          width = value
+          if (value > 0)
+            env.art.emit('destroy')
+        },
+      })
+    }
+    return element
+  }
+  env.metadata()
+  assert.deepEqual([env.canvases[0].width, env.canvases[0].height], [0, 0])
+  assert.equal(env.attached.size, 0)
+  assert.equal(env.blobs.length, 0)
+})