Allow setting a test environment per file

docs/Configuration.md

@@ -318,7 +318,18 @@ To make a dependency explicit instead of implicit, you can call [`expect.addSnap
 ### `testEnvironment` [string]
 Default: `"jsdom"`
 
-The test environment that will be used for testing. The default environment in Jest is a browser-like environment through [jsdom](https://github.com/tmpvar/jsdom). If you are building a node service, you can use the `node` option to use a node-like environment instead. Combining the test environments is currently not possible but the `jsdom` environment can be seen as a superset of the `node` one.
+The test environment that will be used for testing. The default environment in Jest is a browser-like environment through [jsdom](https://github.com/tmpvar/jsdom). If you are building a node service, you can use the `node` option to use a node-like environment instead. If some tests require another environment, you can add a `@testEnvironment` pragma.
+
+```js
+/**
+ * @testEnvironment jsdom
+ */
+
+test('use document in a mostly node environment', () => {
+  const ele = document.createElement('div');
+  expect(ele).not.toBeNull();
+});
+```
 
 You can create your own module that will be used for setting up the test environment. The module must export a class with `runScript` and `dispose` methods. See the [node](https://github.com/facebook/jest/blob/master/packages/jest-environment-node/src/index.js) or [jsdom](https://github.com/facebook/jest/blob/master/packages/jest-environment-jsdom/src/index.js) environments as examples.
 

integration_tests/__tests__/test-environment-test.js

@@ -0,0 +1,23 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc. All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @emails oncall+jsinfra
+ */
+'use strict';
+
+const runJest = require('../runJest');
+
+const testFixturePackage = require('../test-environment/package.json');
+
+it('respects testEnvironment pragma', () => {
+  expect(testFixturePackage.jest.testEnvironment).toEqual('node');
+
+  const result = runJest.json('test-environment').json;
+
+  expect(result.success).toBe(true);
+  expect(result.numTotalTests).toBe(1);
+});

integration_tests/test-environment/__tests__/env-test.js

@@ -0,0 +1,19 @@
+/* eslint-env browser */
+
+/**
+ * Copyright (c) 2014-present, Facebook, Inc. All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+'use strict';
+
+/**
+ * @testEnvironment jsdom
+ */
+
+test('stub', () => {
+  const ele = document.createElement('div');
+  expect(ele).not.toBeNull();
+});

integration_tests/test-environment/package.json

@@ -0,0 +1,5 @@
+{
+  "jest": {
+    "testEnvironment": "node"
+  }
+}

packages/jest-cli/src/runTest.js

@@ -13,74 +13,91 @@ import type {Path, Config} from 'types/Config';
 import type {TestResult} from 'types/TestResult';
 import type {Resolver} from 'types/Resolve';
 
+const fs = require('fs');
+const {getTestEnvironment} = require('jest-config');
 const BufferedConsole = require('./lib/BufferedConsole');
+const promisify = require('./lib/promisify');
 const {
   Console,
   NullConsole,
   setGlobal,
 } = require('jest-util');
 const getConsoleOutput = require('./reporters/getConsoleOutput');
 
+const testEnvironmentPragmaRegex = /@testEnvironment\s+(.*)/;
+
 function runTest(path: Path, config: Config, resolver: Resolver) {
-  /* $FlowFixMe */
-  const TestEnvironment = require(config.testEnvironment);
-  /* $FlowFixMe */
-  const TestRunner = require(config.testRunner);
-  /* $FlowFixMe */
-  const ModuleLoader = require(config.moduleLoader || 'jest-runtime');
+  return promisify(fs.readFile)(path, 'utf8').then(data => {
+    let testEnvironment = config.testEnvironment;
+
+    const testEnvironmentPragma = data.match(testEnvironmentPragmaRegex);
 
-  const env = new TestEnvironment(config);
-  const TestConsole =
-    config.verbose
-      ? Console
-      : (config.silent
-        ? NullConsole
-        : BufferedConsole
+    if (testEnvironmentPragma && testEnvironmentPragma.length > 1) {
+      testEnvironment = getTestEnvironment(
+        Object.assign({}, config, {testEnvironment: testEnvironmentPragma[1]})
       );
-  const testConsole = new TestConsole(
-    config.useStderr ? process.stderr : process.stdout,
-    process.stderr,
-    (type, message) => getConsoleOutput(
-      config.rootDir,
-      !!config.verbose,
-      // 4 = the console call is burried 4 stack frames deep
-      BufferedConsole.write([], type, message, 4),
-    ),
-  );
-  setGlobal(env.global, 'console', testConsole);
-  const runtime = new ModuleLoader(config, env, resolver);
-  const start = Date.now();
-  return TestRunner(config, env, runtime, path)
-    .then((result: TestResult) => {
-      const testCount =
-        result.numPassingTests +
-        result.numFailingTests +
-        result.numPendingTests;
-      result.perfStats = {end: Date.now(), start};
-      result.testFilePath = path;
-      result.coverage = runtime.getAllCoverageInfo();
-      result.console = testConsole.getBuffer();
-      result.skipped = testCount === result.numPendingTests;
-      return result;
-    })
-    .then(
-      result => Promise.resolve().then(() => {
-        env.dispose();
-        if (config.logHeapUsage) {
-          if (global.gc) {
-            global.gc();
-          }
-          result.memoryUsage = process.memoryUsage().heapUsed;
-        }
+    }
+
+    /* $FlowFixMe */
+    const TestEnvironment = require(testEnvironment);
+    /* $FlowFixMe */
+    const TestRunner = require(config.testRunner);
+    /* $FlowFixMe */
+    const ModuleLoader = require(config.moduleLoader || 'jest-runtime');
 
-        // Delay the resolution to allow log messages to be output.
-        return new Promise(resolve => setImmediate(() => resolve(result)));
-      }),
-      err => Promise.resolve().then(() => {
-        env.dispose();
-        throw err;
-      }),
+    const env = new TestEnvironment(config);
+    const TestConsole =
+      config.verbose
+        ? Console
+        : (config.silent
+          ? NullConsole
+          : BufferedConsole
+        );
+    const testConsole = new TestConsole(
+      config.useStderr ? process.stderr : process.stdout,
+      process.stderr,
+      (type, message) => getConsoleOutput(
+        config.rootDir,
+        !!config.verbose,
+        // 4 = the console call is buried 4 stack frames deep
+        BufferedConsole.write([], type, message, 4),
+      ),
     );
+    setGlobal(env.global, 'console', testConsole);
+    const runtime = new ModuleLoader(config, env, resolver);
+    const start = Date.now();
+    return TestRunner(config, env, runtime, path)
+      .then((result: TestResult) => {
+        const testCount =
+          result.numPassingTests +
+          result.numFailingTests +
+          result.numPendingTests;
+        result.perfStats = {end: Date.now(), start};
+        result.testFilePath = path;
+        result.coverage = runtime.getAllCoverageInfo();
+        result.console = testConsole.getBuffer();
+        result.skipped = testCount === result.numPendingTests;
+        return result;
+      })
+      .then(
+        result => Promise.resolve().then(() => {
+          env.dispose();
+          if (config.logHeapUsage) {
+            if (global.gc) {
+              global.gc();
+            }
+            result.memoryUsage = process.memoryUsage().heapUsed;
+          }
+
+          // Delay the resolution to allow log messages to be output.
+          return new Promise(resolve => setImmediate(() => resolve(result)));
+        }),
+        err => Promise.resolve().then(() => {
+          env.dispose();
+          throw err;
+        }),
+      );
+  });
 }
 
 module.exports = runTest;

packages/jest-config/src/index.js

@@ -15,6 +15,7 @@ const loadFromFile = require('./loadFromFile');
 const loadFromPackage = require('./loadFromPackage');
 const normalize = require('./normalize');
 const setFromArgv = require('./setFromArgv');
+const {getTestEnvironment} = require('./utils');
 
 const readConfig = (argv: Object, packageRoot: string) =>
   readRawConfig(argv, packageRoot)
@@ -60,6 +61,7 @@ const readRawConfig = (argv, root) => {
 };
 
 module.exports = {
+  getTestEnvironment,
   normalize,
   readConfig,
 };