[Proposal] Watch plugins API

CHANGELOG.md

@@ -43,6 +43,11 @@
   to the absolute path. Additionally, this fixes functionality in Windows OS.
   ([#5398](https://github.com/facebook/jest/pull/5398))
 
+### Chore & Maintenance
+
+* `[jest-util]` Implement watch plugins
+  ([#5399](https://github.com/facebook/jest/pull/5399))
+
 ## jest 22.1.4
 
 ### Fixes

packages/jest-cli/src/__tests__/__snapshots__/watch.test.js.snap

@@ -30,9 +30,9 @@ Watch Usage
  › Press f to run only failed tests.
  › Press p to filter by a filename regex pattern.
  › Press t to filter by a test name regex pattern.
+ › Press q to quit watch mode.
  › Press s to do nothing.
  › Press u to do something else.
- › Press q to quit watch mode.
  › Press Enter to trigger a test run.
 ",
   ],
@@ -46,10 +46,10 @@ Array [
 Watch Usage
  › Press a to run all tests.
  › Press f to run only failed tests.
- › Press u to update failing snapshots.
- › Press i to update failing snapshots interactively.
  › Press p to filter by a filename regex pattern.
  › Press t to filter by a test name regex pattern.
+ › Press u to update failing snapshots.
+ › Press i to update failing snapshots interactively.
  › Press q to quit watch mode.
  › Press Enter to trigger a test run.
 ",
@@ -64,9 +64,9 @@ Array [
 Watch Usage
  › Press a to run all tests.
  › Press f to run only failed tests.
- › Press u to update failing snapshots.
  › Press p to filter by a filename regex pattern.
  › Press t to filter by a test name regex pattern.
+ › Press u to update failing snapshots.
  › Press q to quit watch mode.
  › Press Enter to trigger a test run.
 ",

packages/jest-cli/src/__tests__/watch.test.js

@@ -35,25 +35,36 @@ jest.doMock(
 
 jest.doMock(
   watchPluginPath,
-  () => ({
-    enter: jest.fn(),
-    key: 's'.codePointAt(0),
-    prompt: 'do nothing',
-  }),
+  () =>
+    class WatchPlugin1 {
+      getUsageRow() {
+        return {
+          key: 's'.codePointAt(0),
+          prompt: 'do nothing',
+        };
+      }
+    },
   {virtual: true},
 );
 
 jest.doMock(
   watchPlugin2Path,
-  () => ({
-    enter: jest.fn(),
-    key: 'u'.codePointAt(0),
-    prompt: 'do something else',
-  }),
+  () =>
+    class WatchPlugin2 {
+      getUsageRow() {
+        return {
+          key: 'u'.codePointAt(0),
+          prompt: 'do something else',
+        };
+      }
+    },
   {virtual: true},
 );
 
 const watch = require('../watch').default;
+
+const nextTick = () => new Promise(res => process.nextTick(res));
+
 afterEach(runJestMock.mockReset);
 
 describe('Watch mode flows', () => {
@@ -231,50 +242,108 @@ describe('Watch mode flows', () => {
     expect(pipeMockCalls.slice(determiningTestsToRun + 1)).toMatchSnapshot();
   });
 
-  it('triggers enter on a WatchPlugin when its key is pressed', () => {
-    const plugin = require(watchPluginPath);
+  it('triggers enter on a WatchPlugin when its key is pressed', async () => {
+    const showPrompt = jest.fn(() => Promise.resolve());
+    const pluginPath = `${__dirname}/__fixtures__/plugin_path`;
+    jest.doMock(
+      pluginPath,
+      () =>
+        class WatchPlugin1 {
+          constructor() {
+            this.showPrompt = showPrompt;
+          }
+          getUsageRow() {
+            return {
+              key: 's'.codePointAt(0),
+              prompt: 'do nothing',
+            };
+          }
+        },
+      {virtual: true},
+    );
 
     watch(
       Object.assign({}, globalConfig, {
         rootDir: __dirname,
-        watchPlugins: [watchPluginPath],
+        watchPlugins: [pluginPath],
       }),
       contexts,
       pipe,
       hasteMapInstances,
       stdin,
     );
 
-    stdin.emit(plugin.key.toString(16));
+    stdin.emit(Number('s'.charCodeAt(0)).toString(16));
+
+    await nextTick();
 
-    expect(plugin.enter).toHaveBeenCalled();
+    expect(showPrompt).toHaveBeenCalled();
   });
 
-  it('prevents Jest from handling keys when active and returns control when end is called', () => {
-    const plugin = require(watchPluginPath);
-    const plugin2 = require(watchPlugin2Path);
+  it('prevents Jest from handling keys when active and returns control when end is called', async () => {
+    let resolveShowPrompt;
+    const showPrompt = jest.fn(
+      () => new Promise(res => (resolveShowPrompt = res)),
+    );
+    const pluginPath = `${__dirname}/__fixtures__/plugin_path_1`;
+    jest.doMock(
+      pluginPath,
+      () =>
+        class WatchPlugin1 {
+          constructor() {
+            this.showPrompt = showPrompt;
+          }
+          onData() {}
+          getUsageRow() {
+            return {
+              key: 's'.codePointAt(0),
+              prompt: 'do nothing',
+            };
+          }
+        },
+      {virtual: true},
+    );
 
-    let pluginEnd;
-    plugin.enter = jest.fn((globalConfig, end) => (pluginEnd = end));
+    const showPrompt2 = jest.fn(() => Promise.resolve());
+    const pluginPath2 = `${__dirname}/__fixtures__/plugin_path_2`;
+    jest.doMock(
+      pluginPath2,
+      () =>
+        class WatchPlugin1 {
+          constructor() {
+            this.showPrompt = showPrompt2;
+          }
+          onData() {}
+          getUsageRow() {
+            return {
+              key: 'z'.codePointAt(0),
+              prompt: 'also do nothing',
+            };
+          }
+        },
+      {virtual: true},
+    );
 
     watch(
       Object.assign({}, globalConfig, {
         rootDir: __dirname,
-        watchPlugins: [watchPluginPath, watchPlugin2Path],
+        watchPlugins: [pluginPath, pluginPath2],
       }),
       contexts,
       pipe,
       hasteMapInstances,
       stdin,
     );
 
-    stdin.emit(plugin.key.toString(16));
-    expect(plugin.enter).toHaveBeenCalled();
-    stdin.emit(plugin2.key.toString(16));
-    expect(plugin2.enter).not.toHaveBeenCalled();
-    pluginEnd();
-    stdin.emit(plugin2.key.toString(16));
-    expect(plugin2.enter).toHaveBeenCalled();
+    stdin.emit(Number('s'.charCodeAt(0)).toString(16));
+    await nextTick();
+    expect(showPrompt).toHaveBeenCalled();
+    stdin.emit(Number('z'.charCodeAt(0)).toString(16));
+    await nextTick();
+    expect(showPrompt2).not.toHaveBeenCalled();
+    await resolveShowPrompt();
+    stdin.emit(Number('z'.charCodeAt(0)).toString(16));
+    expect(showPrompt2).toHaveBeenCalled();
   });
 
   it('Pressing "o" runs test in "only changed files" mode', () => {
@@ -312,20 +381,22 @@ describe('Watch mode flows', () => {
     expect(runJestMock).toHaveBeenCalledTimes(2);
   });
 
-  it('Pressing "u" reruns the tests in "update snapshot" mode', () => {
+  it('Pressing "u" reruns the tests in "update snapshot" mode', async () => {
     globalConfig.updateSnapshot = 'new';
 
     watch(globalConfig, contexts, pipe, hasteMapInstances, stdin);
     runJestMock.mockReset();
 
     stdin.emit(KEYS.U);
+    await nextTick();
 
     expect(runJestMock.mock.calls[0][0].globalConfig).toMatchObject({
       updateSnapshot: 'all',
       watch: true,
     });
 
     stdin.emit(KEYS.A);
+    await nextTick();
     // updateSnapshot is not sticky after a run.
     expect(runJestMock.mock.calls[1][0].globalConfig).toMatchObject({
       updateSnapshot: 'new',

packages/jest-cli/src/__tests__/watch_filename_pattern_mode.test.js

@@ -85,6 +85,8 @@ jest.doMock('../lib/terminal_utils', () => ({
 
 const watch = require('../watch').default;
 
+const nextTick = () => new Promise(res => process.nextTick(res));
+
 const toHex = char => Number(char.charCodeAt(0)).toString(16);
 
 const globalConfig = {watch: true};
@@ -142,27 +144,35 @@ describe('Watch mode flows', () => {
     });
   });
 
-  it('Pressing "c" clears the filters', () => {
+  it('Pressing "c" clears the filters', async () => {
     contexts[0].config = {rootDir: ''};
     watch(globalConfig, contexts, pipe, hasteMapInstances, stdin);
 
     stdin.emit(KEYS.P);
+    await nextTick();
 
     ['p', '.', '*', '1', '0']
       .map(toHex)
       .concat(KEYS.ENTER)
       .forEach(key => stdin.emit(key));
 
     stdin.emit(KEYS.T);
+    await nextTick();
+
     ['t', 'e', 's', 't']
       .map(toHex)
       .concat(KEYS.ENTER)
       .forEach(key => stdin.emit(key));
 
+    await nextTick();
+
     stdin.emit(KEYS.C);
+    await nextTick();
 
     pipe.write.mockReset();
     stdin.emit(KEYS.P);
+    await nextTick();
+
     expect(pipe.write.mock.calls.join('\n')).toMatchSnapshot();
   });
 });

packages/jest-cli/src/jest_hooks.js

@@ -0,0 +1,65 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc. 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 type {AggregatedResult} from 'types/TestResult';
+
+type ShouldRunTestSuite = (testPath: string) => Promise<boolean>;
+type TestRunComplete = (results: AggregatedResult) => void;
+
+export type JestHookSubscriber = {
+  shouldRunTestSuite: (fn: ShouldRunTestSuite) => void,
+  testRunComplete: (fn: TestRunComplete) => void,
+};
+
+export type JestHookEmitter = {
+  shouldRunTestSuite: (testPath: string) => Promise<boolean>,
+  testRunComplete: (results: AggregatedResult) => void,
+};
+
+class JestHooks {
+  _listeners: {
+    shouldRunTestSuite: Array<ShouldRunTestSuite>,
+    testRunComplete: Array<TestRunComplete>,
+  };
+
+  constructor() {
+    this._listeners = {
+      shouldRunTestSuite: [],
+      testRunComplete: [],
+    };
+  }
+
+  getSubscriber(): JestHookSubscriber {
+    return {
+      shouldRunTestSuite: fn => {
+        this._listeners.shouldRunTestSuite.push(fn);
+      },
+      testRunComplete: fn => {
+        this._listeners.testRunComplete.push(fn);
+      },
+    };
+  }
+
+  getEmitter(): JestHookEmitter {
+    return {
+      shouldRunTestSuite: async testPath =>
+        Promise.all(
+          this._listeners.shouldRunTestSuite.map(listener =>
+            listener(testPath),
+          ),
+        ).then(result =>
+          result.every(shouldRunTestSuite => shouldRunTestSuite),
+        ),
+      testRunComplete: results =>
+        this._listeners.testRunComplete.forEach(listener => listener(results)),
+    };
+  }
+}
+
+export default JestHooks;

packages/jest-cli/src/lib/active_filters_message.js

@@ -0,0 +1,37 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc. 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 type {GlobalConfig} from 'types/Config';
+import chalk from 'chalk';
+
+const activeFilters = (
+  globalConfig: GlobalConfig,
+  delimiter: string = '\n',
+) => {
+  const {testNamePattern, testPathPattern} = globalConfig;
+  if (testNamePattern || testPathPattern) {
+    const filters = [
+      testPathPattern
+        ? chalk.dim('filename ') + chalk.yellow('/' + testPathPattern + '/')
+        : null,
+      testNamePattern
+        ? chalk.dim('test name ') + chalk.yellow('/' + testNamePattern + '/')
+        : null,
+    ]
+      .filter(f => f)
+      .join(', ');
+
+    const messages = ['\n' + chalk.bold('Active Filters: ') + filters];
+
+    return messages.filter(message => !!message).join(delimiter);
+  }
+
+  return '';
+};
+
+export default activeFilters;