Initial implementation of Jest test runner for RN integration tests (#47558)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/47558

Changelog: [internal]

Reviewed By: sammy-SC

Differential Revision: D65661701

fbshipit-source-id: 0f0227debc769d0cebebc1989cbcfbbdd44dfc34

.gitignore

@@ -155,3 +155,6 @@ vendor/
 
 # CircleCI
 .circleci/generated_config.yml
+
+# Jest Integration
+/jest/integration/build/

jest/integration/config/jest.config.js

@@ -0,0 +1,27 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+'use strict';
+
+const baseConfig = require('../../../jest.config');
+const path = require('path');
+
+module.exports = {
+  rootDir: path.resolve(__dirname, '../../..'),
+  roots: [
+    '<rootDir>/packages/react-native',
+    '<rootDir>/jest/integration/runtime',
+  ],
+  // This allows running Meta-internal tests with the `-test.fb.js` suffix.
+  testRegex: '/__tests__/.*-itest(\\.fb)?\\.js$',
+  testPathIgnorePatterns: baseConfig.testPathIgnorePatterns,
+  transformIgnorePatterns: ['.*'],
+  testRunner: './jest/integration/runner/index.js',
+  watchPathIgnorePatterns: ['<rootDir>/jest/integration/build/'],
+};

jest/integration/config/metro-babel-transformer.js

@@ -0,0 +1,13 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+'use strict';
+
+require('../../../scripts/build/babel-register').registerForMonorepo();
+module.exports = require('@react-native/metro-babel-transformer');

jest/integration/config/metro.config.js

@@ -0,0 +1,40 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+'use strict';
+
+const {getDefaultConfig} = require('@react-native/metro-config');
+const {mergeConfig} = require('metro-config');
+const path = require('path');
+
+const rnTesterConfig = getDefaultConfig(
+  path.resolve('../../../packages/rn-tester'),
+);
+
+const config = {
+  projectRoot: path.resolve(__dirname, '../../..'),
+  reporter: {
+    update: () => {},
+  },
+  resolver: {
+    blockList: null,
+    sourceExts: [...rnTesterConfig.resolver.sourceExts, 'fb.js'],
+    nodeModulesPaths: process.env.JS_DIR
+      ? [path.join(process.env.JS_DIR, 'public', 'node_modules')]
+      : [],
+  },
+  transformer: {
+    // We need to wrap the default transformer so we can run it from source
+    // using babel-register.
+    babelTransformerPath: path.resolve(__dirname, 'metro-babel-transformer.js'),
+  },
+  watchFolders: process.env.JS_DIR ? [process.env.JS_DIR] : [],
+};
+
+module.exports = mergeConfig(rnTesterConfig, config);

jest/integration/runner/entrypoint-template.js

@@ -0,0 +1,28 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @oncall react_native
+ */
+
+module.exports = function entrypointTemplate({testPath, setupModulePath}) {
+  return `/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * ${'@'}generated
+ * @noformat
+ * @noflow
+ * @oncall react_native
+ */
+
+import {registerTest} from '${setupModulePath}';
+
+registerTest(() => require('${testPath}'));
+`;
+};

jest/integration/runner/index.js

@@ -0,0 +1,201 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @oncall react_native
+ */
+
+'use strict';
+
+const entrypointTemplate = require('./entrypoint-template');
+const {spawnSync} = require('child_process');
+const crypto = require('crypto');
+const fs = require('fs');
+const {formatResultsErrors} = require('jest-message-util');
+const Metro = require('metro');
+const nullthrows = require('nullthrows');
+const os = require('os');
+const path = require('path');
+
+const BUILD_OUTPUT_PATH = path.resolve(__dirname, '..', 'build');
+
+function parseRNTesterCommandResult(commandArgs, result) {
+  const stdout = result.stdout.toString();
+
+  const outputArray = stdout.trim().split('\n');
+
+  // Remove AppRegistry logs at the end
+  while (
+    outputArray.length > 0 &&
+    outputArray[outputArray.length - 1].startsWith('Running "')
+  ) {
+    outputArray.pop();
+  }
+
+  // The last line should be the test output in JSON format
+  const testResultJSON = outputArray.pop();
+
+  let testResult;
+  try {
+    testResult = JSON.parse(nullthrows(testResultJSON));
+  } catch (error) {
+    throw new Error(
+      [
+        'Failed to parse test results from RN tester binary result. Full output:',
+        'buck2 ' + commandArgs.join(' '),
+        'stdout:',
+        stdout,
+        'stderr:',
+        result.stderr.toString(),
+      ].join('\n'),
+    );
+  }
+
+  return {logs: outputArray.join('\n'), testResult};
+}
+
+function getBuckModeForPlatform() {
+  switch (os.platform()) {
+    case 'linux':
+      return '@//arvr/mode/linux/dev';
+    case 'darwin':
+      return os.arch() === 'arm64'
+        ? '@//arvr/mode/mac-arm/dev'
+        : '@//arvr/mode/mac/dev';
+    case 'win32':
+      return '@//arvr/mode/win/dev';
+    default:
+      throw new Error(`Unsupported platform: ${os.platform()}`);
+  }
+}
+
+function getShortHash(contents) {
+  return crypto.createHash('md5').update(contents).digest('hex').slice(0, 8);
+}
+
+module.exports = async function runTest(
+  globalConfig,
+  config,
+  environment,
+  runtime,
+  testPath,
+  sendMessageToJest,
+) {
+  const startTime = Date.now();
+
+  const metroConfig = await Metro.loadConfig({
+    config: require.resolve('../config/metro.config.js'),
+  });
+
+  const setupModulePath = path.resolve(__dirname, '../runtime/setup.js');
+
+  const entrypointContents = entrypointTemplate({
+    testPath: `.${path.sep}${path.relative(BUILD_OUTPUT_PATH, testPath)}`,
+    setupModulePath: `.${path.sep}${path.relative(BUILD_OUTPUT_PATH, setupModulePath)}`,
+  });
+
+  const entrypointPath = path.join(
+    BUILD_OUTPUT_PATH,
+    `${getShortHash(entrypointContents)}-${path.basename(testPath)}`,
+  );
+  const testBundlePath = entrypointPath + '.bundle';
+
+  fs.mkdirSync(path.dirname(entrypointPath), {recursive: true});
+  fs.writeFileSync(entrypointPath, entrypointContents, 'utf8');
+
+  await Metro.runBuild(metroConfig, {
+    entry: entrypointPath,
+    out: testBundlePath,
+    platform: 'android',
+    minify: false,
+    dev: true,
+  });
+
+  const rnTesterCommandArgs = [
+    'run',
+    getBuckModeForPlatform(),
+    '//xplat/ReactNative/react-native-cxx/samples/tester:tester',
+    '--',
+    `--bundlePath=${testBundlePath}`,
+  ];
+  const rnTesterCommandResult = spawnSync('buck2', rnTesterCommandArgs, {
+    encoding: 'utf8',
+  });
+
+  if (rnTesterCommandResult.status !== 0) {
+    throw new Error(
+      [
+        'Failed to run test in RN tester binary. Full output:',
+        'buck2 ' + rnTesterCommandArgs.join(' '),
+        'stdout:',
+        rnTesterCommandResult.stdout,
+        'stderr:',
+        rnTesterCommandResult.stderr,
+      ].join('\n'),
+    );
+  }
+
+  const rnTesterParsedOutput = parseRNTesterCommandResult(
+    rnTesterCommandArgs,
+    rnTesterCommandResult,
+  );
+
+  const testResultError = rnTesterParsedOutput.testResult.error;
+  if (testResultError) {
+    const error = new Error(testResultError.message);
+    error.stack = testResultError.stack;
+    throw error;
+  }
+
+  const endTime = Date.now();
+
+  console.log(rnTesterParsedOutput.logs);
+
+  const testResults =
+    nullthrows(rnTesterParsedOutput.testResult.testResults).map(testResult => ({
+      ancestorTitles: [],
+      failureDetails: [],
+      testFilePath: testPath,
+      ...testResult,
+    })) ?? [];
+
+  return {
+    testFilePath: testPath,
+    failureMessage: formatResultsErrors(
+      testResults,
+      config,
+      globalConfig,
+      testPath,
+    ),
+    leaks: false,
+    openHandles: [],
+    perfStats: {
+      start: startTime,
+      end: endTime,
+      duration: endTime - startTime,
+      runtime: endTime - startTime,
+      slow: false,
+    },
+    snapshot: {
+      added: 0,
+      fileDeleted: false,
+      matched: 0,
+      unchecked: 0,
+      uncheckedKeys: [],
+      unmatched: 0,
+      updated: 0,
+    },
+    numTotalTests: testResults.length,
+    numPassingTests: testResults.filter(test => test.status === 'passed')
+      .length,
+    numFailingTests: testResults.filter(test => test.status === 'failed')
+      .length,
+    numPendingTests: 0,
+    numTodoTests: 0,
+    skipped: false,
+    testResults,
+  };
+};

jest/integration/runtime/setup.js

@@ -0,0 +1,180 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow strict-local
+ * @format
+ * @oncall react_native
+ */
+
+import nullthrows from 'nullthrows';
+
+export type TestCaseResult = {
+  ancestorTitles: Array<string>,
+  title: string,
+  fullName: string,
+  status: 'passed' | 'failed' | 'pending',
+  duration: number,
+  failureMessages: Array<string>,
+  numPassingAsserts: number,
+  // location: string,
+};
+
+export type TestSuiteResult =
+  | {
+      testResults: Array<TestCaseResult>,
+    }
+  | {
+      error: {
+        message: string,
+        stack: string,
+      },
+    };
+
+const tests: Array<{
+  title: string,
+  ancestorTitles: Array<string>,
+  implementation: () => mixed,
+  result?: TestCaseResult,
+}> = [];
+
+const ancestorTitles: Array<string> = [];
+
+global.describe = (title: string, implementation: () => mixed) => {
+  ancestorTitles.push(title);
+  implementation();
+  ancestorTitles.pop();
+};
+
+global.it = (title: string, implementation: () => mixed) =>
+  tests.push({
+    title,
+    implementation,
+    ancestorTitles: ancestorTitles.slice(),
+  });
+
+// flowlint unsafe-getters-setters:off
+
+class Expect {
+  #received: mixed;
+  #isNot: boolean = false;
+
+  constructor(received: mixed) {
+    this.#received = received;
+  }
+
+  get not(): this {
+    this.#isNot = !this.#isNot;
+    return this;
+  }
+
+  toBe(expected: mixed): void {
+    const pass = this.#received !== expected;
+    if (this.#isExpectedResult(pass)) {
+      throw new Error(
+        `Expected ${String(expected)} but received ${String(this.#received)}.`,
+      );
+    }
+  }
+
+  toBeInstanceOf(expected: Class<mixed>): void {
+    const pass = this.#received instanceof expected;
+    if (!pass) {
+      throw new Error(
+        `expected ${String(this.#received)} to be an instance of ${String(expected)}`,
+      );
+    }
+  }
+
+  toBeCloseTo(expected: number, precision: number = 2): void {
+    const pass =
+      Math.abs(expected - Number(this.#received)) < Math.pow(10, -precision);
+    if (!pass) {
+      throw new Error(
+        `expected ${String(this.#received)} to be close to ${expected}`,
+      );
+    }
+  }
+
+  toThrow(error: mixed): void {
+    if (error != null) {
+      throw new Error('toThrow() implementation does not accept arguments.');
+    }
+
+    let pass = false;
+    try {
+      // $FlowExpectedError[not-a-function]
+      this.#received();
+    } catch {
+      pass = true;
+    }
+    if (!pass) {
+      throw new Error(`expected ${String(this.#received)} to throw`);
+    }
+  }
+
+  #isExpectedResult(pass: boolean): boolean {
+    return this.#isNot ? !pass : pass;
+  }
+}
+
+global.expect = (received: mixed) => new Expect(received);
+
+function runWithGuard(fn: () => void) {
+  try {
+    fn();
+  } catch (error) {
+    let reportedError =
+      error instanceof Error ? error : new Error(String(error));
+    reportTestSuiteResult({
+      error: {
+        message: reportedError.message,
+        stack: reportedError.stack,
+      },
+    });
+  }
+}
+
+function executeTests() {
+  for (const test of tests) {
+    let status;
+    let error;
+
+    const start = Date.now();
+
+    try {
+      test.implementation();
+      status = 'passed';
+    } catch (e) {
+      error = e;
+      status = 'failed';
+    }
+
+    test.result = {
+      title: test.title,
+      fullName: [...test.ancestorTitles, test.title].join(' '),
+      ancestorTitles: test.ancestorTitles,
+      status,
+      duration: Date.now() - start,
+      failureMessages: status === 'failed' && error ? [error.message] : [],
+      numPassingAsserts: 0,
+    };
+  }
+
+  reportTestSuiteResult({
+    testResults: tests.map(test => nullthrows(test.result)),
+  });
+}
+
+function reportTestSuiteResult(testSuiteResult: TestSuiteResult): void {
+  console.log(JSON.stringify(testSuiteResult));
+}
+
+export function registerTest(setUpTest: () => void) {
+  runWithGuard(() => {
+    setUpTest();
+    executeTests();
+  });
+}