Fix encoding of large snapshot data

* Encode snapshot data asynchronously, fixes #2932
* Async I/O when saving snapshots

Author: novemberborn

lib/runner.js

@@ -224,8 +224,8 @@ export default class Runner extends Emittery {
 		return this.snapshots.skipSnapshot(options);
 	}
 
-	saveSnapshotState() {
-		return {touchedFiles: this.snapshots.save()};
+	async saveSnapshotState() {
+		return {touchedFiles: await this.snapshots.save()};
 	}
 
 	onRun(runnable) {

lib/snapshot-manager.js

@@ -182,8 +182,8 @@ function sortBlocks(blocksByTitle, blockIndices) {
 	);
 }
 
-function encodeSnapshots(snapshotData) {
-	const encoded = cbor.encodeOne(snapshotData, {
+async function encodeSnapshots(snapshotData) {
+	const encoded = await cbor.encodeAsync(snapshotData, {
 		omitUndefinedProperties: true,
 		canonical: true,
 	});
@@ -351,7 +351,7 @@ class Manager {
 		this.recordSerialized({belongsTo, index, ...snapshot});
 	}
 
-	save() {
+	async save() {
 		const {dir, relFile, snapFile, snapPath, reportPath} = this;
 
 		if (this.updating && this.newBlocksByTitle.size === 0) {
@@ -371,15 +371,17 @@ class Manager {
 			),
 		};
 
-		const buffer = encodeSnapshots(snapshots);
+		const buffer = await encodeSnapshots(snapshots);
 		const reportBuffer = generateReport(relFile, snapFile, snapshots);
 
-		fs.mkdirSync(dir, {recursive: true});
+		await fs.promises.mkdir(dir, {recursive: true});
 
 		const temporaryFiles = [];
 		const tmpfileCreated = file => temporaryFiles.push(file);
-		writeFileAtomic.sync(snapPath, buffer, {tmpfileCreated});
-		writeFileAtomic.sync(reportPath, reportBuffer, {tmpfileCreated});
+		await Promise.all([
+			writeFileAtomic(snapPath, buffer, {tmpfileCreated}),
+			writeFileAtomic(reportPath, reportBuffer, {tmpfileCreated}),
+		]);
 		return {
 			changedFiles: [snapPath, reportPath],
 			temporaryFiles,

lib/worker/base.js

@@ -81,7 +81,7 @@ const run = async options => {
 
 	runner.on('finish', async () => {
 		try {
-			const {touchedFiles} = runner.saveSnapshotState();
+			const {touchedFiles} = await runner.saveSnapshotState();
 			if (touchedFiles) {
 				channel.send({type: 'touched-files', files: touchedFiles});
 			}

test-tap/assert.js

@@ -1303,7 +1303,7 @@ test('.notThrowsAsync() fails if passed a bad value', t => {
 	t.end();
 });
 
-test('.snapshot()', t => {
+test('.snapshot()', async t => {
 	// Set to `true` to update the snapshot, then run:
 	// npx tap test-tap/assert.js
 	//
@@ -1411,7 +1411,7 @@ test('.snapshot()', t => {
 		});
 	}
 
-	manager.save();
+	await manager.save();
 	t.end();
 });
 

test-tap/try-snapshot.js

@@ -84,5 +84,5 @@ test(async t => {
 		t.equal(result.error.name, 'Error');
 	});
 
-	manager.save();
+	await manager.save();
 });

test/snapshot-regenerate-report/test.js

@@ -38,7 +38,7 @@ test('snapshot report can be regenerated from .snap file', async t => {
 
 	// Regenerate report
 	snapshots.hasChanges = true; // Force.
-	snapshots.save();
+	await snapshots.save();
 
 	// Assert that reports match
 	t.is(await fs.readFile(reportPath, 'utf8'), report);

test/snapshot-tests/fixtures/large/package.json

@@ -0,0 +1 @@
+{}

test/snapshot-tests/fixtures/large/test.js

@@ -0,0 +1,9 @@
+const {Buffer} = require('buffer');
+
+const test = require(process.env.TEST_AVA_IMPORT_FROM);
+
+for (let i = 0; i < 2; i++) {
+	test(`large snapshot ${i}`, t => {
+		t.snapshot(Buffer.alloc(1024 * 16));
+	});
+}

test/snapshot-tests/large.js

@@ -0,0 +1,15 @@
+import test from '@ava/test';
+
+import {cwd, fixture} from '../helpers/exec.js';
+import {withTemporaryFixture} from '../helpers/with-temporary-fixture.js';
+
+// Reproduction for https://github.com/avajs/ava/issues/2932.
+test('can encode and decode large snapshots', async t => {
+	await withTemporaryFixture(cwd('large'), async cwd => {
+		const env = {
+			AVA_FORCE_CI: 'not-ci',
+		};
+		await fixture(['--update-snapshots'], {cwd, env});
+		await t.notThrowsAsync(fixture([], {cwd, env}));
+	});
+});