Hook up error handling to bitmap loading flow and add tests for loading missing and corrupt bitmpas from sb2 and sprite2 files

test/integration/sb2_corrupted_png.js

@@ -0,0 +1,126 @@
+/**
+ * This test mocks render breaking on loading a corrupted bitmap costume.
+ * The VM should handle this safely by displaying a Gray Question Mark,
+ * but keeping track of the original costume data and serializing the
+ * original costume data back out. The saved project.json should not
+ * reflect that the costume is broken and should therefore re-attempt
+ * to load the costume if the saved project is re-loaded.
+ */
+const path = require('path');
+const tap = require('tap');
+const md5 = require('js-md5');
+const makeTestStorage = require('../fixtures/make-test-storage');
+const FakeRenderer = require('../fixtures/fake-renderer');
+const FakeBitmapAdapter = require('../fixtures/fake-bitmap-adapter');
+const {extractAsset, readFileToBuffer} = require('../fixtures/readProjectFile');
+const VirtualMachine = require('../../src/index');
+const {serializeCostumes} = require('../../src/serialization/serialize-assets');
+
+const projectUri = path.resolve(__dirname, '../fixtures/corrupt_png.sb2');
+const project = readFileToBuffer(projectUri);
+const costumeFileName = '1.png';
+const originalCostume = extractAsset(projectUri, costumeFileName);
+// We need to get the actual md5 because we hand modified the png to corrupt it
+// after we downloaded the project from Scratch
+// Loading the project back into the VM will correct the assetId and md5
+const brokenCostumeMd5 = md5(originalCostume);
+
+global.Image = function () {
+    const image = {
+        width: 1,
+        height: 1
+    };
+    setTimeout(() => {
+        const base64Image = image.src.split(',')[1];
+        const decodedText = Buffer.from(base64Image, 'base64').toString();
+        if (decodedText.includes('Here is some')) {
+            image.onerror();
+        } else {
+            image.onload();
+        }
+    }, 1000);
+    return image;
+};
+
+global.document = {
+    createElement: () => ({
+        // Create mock canvas
+        getContext: () => ({
+            drawImage: () => ({})
+        })
+    })
+};
+
+let vm;
+let defaultBitmapAssetId;
+
+tap.beforeEach(() => {
+    const storage = makeTestStorage();
+
+    vm = new VirtualMachine();
+    vm.attachStorage(storage);
+    defaultBitmapAssetId = vm.runtime.storage.defaultAssetId.ImageBitmap;
+
+    vm.attachRenderer(new FakeRenderer());
+    vm.attachV2BitmapAdapter(new FakeBitmapAdapter());
+
+    return vm.loadProject(project);
+});
+
+const test = tap.test;
+
+test('load sb2 project with corrupted bitmap costume file', t => {
+    t.equal(vm.runtime.targets.length, 2);
+    
+    const stage = vm.runtime.targets[0];
+    t.ok(stage.isStage);
+
+    const greenGuySprite = vm.runtime.targets[1];
+    t.equal(greenGuySprite.getName(), 'GreenGuy');
+    t.equal(greenGuySprite.getCostumes().length, 1);
+    
+    const corruptedCostume = greenGuySprite.getCostumes()[0];
+    t.equal(corruptedCostume.name, 'GreenGuy');
+    t.equal(corruptedCostume.assetId, defaultBitmapAssetId);
+    t.equal(corruptedCostume.dataFormat, 'png');
+    // Runtime should have info about broken asset
+    t.ok(corruptedCostume.broken);
+    t.equal(corruptedCostume.broken.assetId, brokenCostumeMd5);
+    // Verify that we saved the original asset data
+    t.equal(md5(corruptedCostume.broken.asset.data), brokenCostumeMd5);
+
+    t.end();
+});
+
+test('load and then save project with corrupted bitmap costume file', t => {
+    const resavedProject = JSON.parse(vm.toJSON());
+
+    t.equal(resavedProject.targets.length, 2);
+    
+    const stage = resavedProject.targets[0];
+    t.ok(stage.isStage);
+
+    const greenGuySprite = resavedProject.targets[1];
+    t.equal(greenGuySprite.name, 'GreenGuy');
+    t.equal(greenGuySprite.costumes.length, 1);
+    
+    const corruptedCostume = greenGuySprite.costumes[0];
+    t.equal(corruptedCostume.name, 'GreenGuy');
+    // Resaved project costume should have the metadata that corresponds to the original broken costume
+    t.equal(corruptedCostume.assetId, brokenCostumeMd5);
+    t.equal(corruptedCostume.dataFormat, 'png');
+    // Test that we didn't save any data about the costume being broken
+    t.notOk(corruptedCostume.broken);
+
+    t.end();
+});
+
+test('serializeCostume saves orignal broken costume', t => {
+    const costumeDescs = serializeCostumes(vm.runtime, vm.runtime.targets[1].id);
+    t.equal(costumeDescs.length, 1);
+    const costume = costumeDescs[0];
+    t.equal(costume.fileName, `${brokenCostumeMd5}.png`);
+    t.equal(md5(costume.fileContent), brokenCostumeMd5);
+    t.end();
+    process.nextTick(process.exit);
+});