Function runTestInternal

packages/jest-runner/src/runTest.ts:79–399

(
  path: string,
  globalConfig: Config.GlobalConfig,
  projectConfig: Config.ProjectConfig,
  resolver: Resolver,
  context: TestRunnerContext,
  sendMessageToJest?: TestFileEvent,
)

// references to verify if there is a leak, which is not maintainable and error
// prone. That's why "runTestInternal" CANNOT be inlined inside "runTest".
async function runTestInternal(
  path: string,
  globalConfig: Config.GlobalConfig,
  projectConfig: Config.ProjectConfig,
  resolver: Resolver,
  context: TestRunnerContext,
  sendMessageToJest?: TestFileEvent,
): Promise<RunTestInternalResult> {
  const testSource = fs.readFileSync(path, 'utf8');
  const docblockPragmas = docblock.parse(docblock.extract(testSource));
  const customEnvironment = docblockPragmas['jest-environment'];

  const loadTestEnvironmentStart = Date.now();
  let testEnvironment = projectConfig.testEnvironment;

  if (customEnvironment) {
    if (Array.isArray(customEnvironment)) {
      throw new TypeError(
        `You can only define a single test environment through docblocks, got "${customEnvironment.join(
          ', ',
        )}"`,
      );
    }
    testEnvironment = resolveTestEnvironment({
      ...projectConfig,
      // we wanna avoid webpack trying to be clever
      requireResolveFunction: module => require.resolve(module),
      testEnvironment: customEnvironment,
    });
  }

  const cacheFS = new Map([[path, testSource]]);
  const transformer = await createScriptTransformer(projectConfig, cacheFS);

  const TestEnvironment: typeof JestEnvironment =
    await transformer.requireAndTranspileModule(testEnvironment);
  const testFramework: TestFramework =
    await transformer.requireAndTranspileModule(
      process.env.JEST_JASMINE === '1'
        ? require.resolve('jest-jasmine2')
        : projectConfig.testRunner,
    );
  const Runtime: typeof RuntimeClass = interopRequireDefault(
    projectConfig.runtime
      ? require(projectConfig.runtime)
      : require('jest-runtime'),
  ).default;

  const consoleOut = globalConfig.useStderr ? process.stderr : process.stdout;
  const consoleFormatter = (type: LogType, message: LogMessage) =>
    getConsoleOutput(
      // 4 = the console call is buried 4 stack frames deep
      BufferedConsole.write([], type, message, 4),
      projectConfig,
      globalConfig,
    );

  let testConsole;