Make Jest’s Test Runner configurable. (jestjs#4240)

integration_tests/__tests__/__snapshots__/show_config.test.js.snap

@@ -34,6 +34,7 @@ exports[`--showConfig outputs config info and exits 1`] = `
       \\"roots\\": [
         \\"<<REPLACED_ROOT_DIR>>\\"
       ],
+      \\"runner\\": \\"jest-runner\\",
       \\"setupFiles\\": [],
       \\"snapshotSerializers\\": [],
       \\"testEnvironment\\": \\"jest-environment-jsdom\\",

packages/jest-cli/src/run_jest.js

@@ -200,7 +200,7 @@ const runJest = async ({
 
   const results = await new TestScheduler(globalConfig, {
     startRun,
-  }).runTests(allTests, testWatcher);
+  }).scheduleTests(allTests, testWatcher);
 
   sequencer.cacheResults(allTests, results);
 

packages/jest-cli/src/test_scheduler.js

@@ -31,6 +31,10 @@ import VerboseReporter from './reporters/verbose_reporter';
 
 const SLOW_TEST_TIME = 3000;
 
+// The default jest-runner is required because it is the default test runner
+// and required implicitly through the `runner` ProjectConfig option.
+TestRunner;
+
 export type TestSchedulerOptions = {|
   startRun: (globalConfig: GlobalConfig) => *,
 |};
@@ -39,12 +43,10 @@ class TestScheduler {
   _dispatcher: ReporterDispatcher;
   _globalConfig: GlobalConfig;
   _options: TestSchedulerOptions;
-  _testRunner: TestRunner;
 
   constructor(globalConfig: GlobalConfig, options: TestSchedulerOptions) {
     this._dispatcher = new ReporterDispatcher();
     this._globalConfig = globalConfig;
-    this._testRunner = new TestRunner(globalConfig);
     this._options = options;
     this._setupReporters();
   }
@@ -57,7 +59,7 @@ class TestScheduler {
     this._dispatcher.unregister(ReporterClass);
   }
 
-  async runTests(tests: Array<Test>, watcher: TestWatcher) {
+  async scheduleTests(tests: Array<Test>, watcher: TestWatcher) {
     const onStart = this._dispatcher.onTestStart.bind(this._dispatcher);
     const timings = [];
     const contexts = new Set();
@@ -138,20 +140,36 @@ class TestScheduler {
       showStatus: !runInBand,
     });
 
-    try {
-      await this._testRunner.runTests(
-        tests,
-        watcher,
-        onStart,
-        onResult,
-        onFailure,
-        {
-          serial: runInBand,
-        },
-      );
-    } catch (error) {
-      if (!watcher.isInterrupted()) {
-        throw error;
+    const testRunners = Object.create(null);
+    contexts.forEach(({config}) => {
+      if (!testRunners[config.runner]) {
+        // $FlowFixMe
+        testRunners[config.runner] = new (require(config.runner): TestRunner)(
+          this._globalConfig,
+        );
+      }
+    });
+
+    const testsByRunner = this._partitionTests(testRunners, tests);
+
+    if (testsByRunner) {
+      try {
+        for (const runner of Object.keys(testRunners)) {
+          await testRunners[runner].runTests(
+            testsByRunner[runner],
+            watcher,
+            onStart,
+            onResult,
+            onFailure,
+            {
+              serial: runInBand,
+            },
+          );
+        }
+      } catch (error) {
+        if (!watcher.isInterrupted()) {
+          throw error;
+        }
       }
     }
 
@@ -174,6 +192,29 @@ class TestScheduler {
     return aggregatedResults;
   }
 
+  _partitionTests(
+    testRunners: {[key: string]: TestRunner},
+    tests: Array<Test>,
+  ) {
+    if (Object.keys(testRunners).length > 1) {
+      return tests.reduce((testRuns, test) => {
+        const runner = test.context.config.runner;
+        if (!testRuns[runner]) {
+          testRuns[runner] = [];
+        }
+        testRuns[runner].push(test);
+        return testRuns;
+      }, Object.create(null));
+    } else if (tests.length > 0 && tests[0] != null) {
+      // If there is only one runner, don't partition the tests.
+      return Object.assign(Object.create(null), {
+        [tests[0].context.config.runner]: tests,
+      });
+    } else {
+      return null;
+    }
+  }
+
   _shouldAddDefaultReporters(reporters?: Array<ReporterConfig>): boolean {
     return (
       !reporters ||

packages/jest-config/src/defaults.js

@@ -52,6 +52,7 @@ module.exports = ({
   preset: null,
   resetMocks: false,
   resetModules: false,
+  runner: 'jest-runner',
   snapshotSerializers: [],
   testEnvironment: 'jest-environment-jsdom',
   testFailureExitCode: 1,

packages/jest-config/src/index.js

@@ -134,6 +134,7 @@ const getConfigs = (
       resolver: options.resolver,
       rootDir: options.rootDir,
       roots: options.roots,
+      runner: options.runner,
       setupFiles: options.setupFiles,
       setupTestFrameworkScriptFile: options.setupTestFrameworkScriptFile,
       skipNodeResolution: options.skipNodeResolution,

packages/jest-config/src/normalize.js

@@ -387,6 +387,7 @@ function normalize(options: InitialOptions, argv: Argv) {
         break;
       case 'moduleLoader':
       case 'resolver':
+      case 'runner':
       case 'setupTestFrameworkScriptFile':
       case 'testResultsProcessor':
       case 'testRunner':

packages/jest-runner/src/run_test.js

@@ -23,9 +23,14 @@ import {
   getConsoleOutput,
   setGlobal,
 } from 'jest-util';
+import jasmine2 from 'jest-jasmine2';
 import {getTestEnvironment} from 'jest-config';
 import docblock from 'jest-docblock';
 
+// The default jest-runner is required because it is the default test runner
+// and required implicitly through the `testRunner` ProjectConfig option.
+jasmine2;
+
 function runTest(
   path: Path,
   globalConfig: GlobalConfig,

test_utils.js

@@ -76,6 +76,7 @@ const DEFAULT_PROJECT_CONFIG: ProjectConfig = {
   resolver: null,
   rootDir: '/test_root_dir/',
   roots: [],
+  runner: 'jest-runner',
   setupFiles: [],
   setupTestFrameworkScriptFile: null,
   skipNodeResolution: false,

types/Config.js

@@ -44,6 +44,7 @@ export type DefaultOptions = {|
   preset: ?string,
   resetMocks: boolean,
   resetModules: boolean,
+  runner: string,
   snapshotSerializers: Array<Path>,
   testEnvironment: string,
   testFailureExitCode: string | number,
@@ -105,6 +106,7 @@ export type InitialOptions = {
   resolver?: ?Path,
   rootDir: Path,
   roots?: Array<Path>,
+  runner?: string,
   scriptPreprocessor?: string,
   setupFiles?: Array<Path>,
   setupTestFrameworkScriptFile?: Path,
@@ -115,8 +117,8 @@ export type InitialOptions = {
   testFailureExitCode?: string | number,
   testMatch?: Array<Glob>,
   testNamePattern?: string,
-  testPathIgnorePatterns?: Array<string>,
   testPathDirs?: Array<Path>,
+  testPathIgnorePatterns?: Array<string>,
   testRegex?: string,
   testResultsProcessor?: ?string,
   testRunner?: string,
@@ -197,6 +199,7 @@ export type ProjectConfig = {|
   resolver: ?Path,
   rootDir: Path,
   roots: Array<Path>,
+  runner: string,
   setupFiles: Array<Path>,
   setupTestFrameworkScriptFile: ?Path,
   skipNodeResolution: boolean,