fix: break dependency cycle in jest-cli

CHANGELOG.md

@@ -4,6 +4,8 @@
 
 ### Fixes
 
+- `[jest-cli]` Break dependency cycle when using Jest programmatically ([#7707](https://github.com/facebook/jest/pull/7707)
+
 ### Chore & Maintenance
 
 - `[website]` Fix broken help link on homepage ([#7706](https://github.com/facebook/jest/pull/7706))

e2e/__tests__/runProgramatically.test.js

@@ -0,0 +1,19 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+import {resolve} from 'path';
+
+import {run} from '../Utils';
+
+const dir = resolve(__dirname, '..', 'run-programatically');
+
+test('run Jest programatically', () => {
+  const {stdout} = run(`node index.js --version`, dir);
+  expect(stdout).toMatch(/\d{2}\.\d{1,2}\.\d{1,2}[\-\S]*-dev$/);
+});

e2e/run-programatically/index.js

@@ -0,0 +1,13 @@
+#!/usr/bin/env node
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+// Running Jest like this is not officially supported,
+// but it is common practice until there is a proper API as a substitute.
+require('jest').run(process.argv);

packages/jest-cli/src/cli/index.js

@@ -33,8 +33,7 @@ import rimraf from 'rimraf';
 import {sync as realpath} from 'realpath-native';
 import init from '../lib/init';
 import logDebugMessages from '../lib/log_debug_messages';
-
-const {getVersion} = require('../jest');
+import getVersion from '../version';
 
 export async function run(maybeArgv?: Argv, project?: Path) {
   try {

packages/jest-cli/src/jest.js

@@ -7,18 +7,17 @@
  * @flow
  */
 
-import {version as VERSION} from '../package.json';
-
 import SearchSource from './SearchSource';
 import TestScheduler from './TestScheduler';
 import TestWatcher from './TestWatcher';
 import {run, runCLI} from './cli';
+import getVersion from './version';
 
 module.exports = {
   SearchSource,
   TestScheduler,
   TestWatcher,
-  getVersion: () => VERSION,
+  getVersion,
   run,
   runCLI,
 };

packages/jest-cli/src/version.js

@@ -0,0 +1,14 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+import {version as VERSION} from '../package.json';
+
+export default function getVersion() {
+  return VERSION;
+}