packager: DependencyGraph-test: go through fs.watch mock rather than manual API

Reviewed By: davidaurelio

Differential Revision: D4628593

fbshipit-source-id: 43ccdb038bd387e87096f2a7020c98d915fa5bba

packages/metro-bundler/src/node-haste/__mocks__/graceful-fs.js

@@ -8,6 +8,7 @@
  */
 'use strict';
 
+const {EventEmitter} = require('events');
 const {dirname} = require.requireActual('path');
 const fs = jest.genMockFromModule('fs');
 const path = require('path');
@@ -96,7 +97,12 @@ fs.readFileSync.mockImplementation(function(filepath, encoding) {
 function makeStatResult(node) {
   const isSymlink = node != null && node.SYMLINK != null;
   return {
+    isBlockDevice: () => false,
+    isCharacterDevice: () => false,
     isDirectory: () => node != null && typeof node === 'object' && !isSymlink,
+    isFIFO: () => false,
+    isFile: () => node != null && typeof node === 'string',
+    isSocket: () => false,
     isSymbolicLink: () => isSymlink,
     mtime,
   };
@@ -242,6 +248,34 @@ fs.createWriteStream.mock.returned = [];
 
 fs.__setMockFilesystem = object => (filesystem = object);
 
+const watcherListByPath = new Map();
+
+fs.watch.mockImplementation((filename, options, listener) => {
+  if (options.recursive) {
+    throw new Error('recursive watch not implemented');
+  }
+  let watcherList = watcherListByPath.get(filename);
+  if (watcherList == null) {
+    watcherList = [];
+    watcherListByPath.set(filename, watcherList);
+  }
+  const fsWatcher = new EventEmitter();
+  fsWatcher.on('change', listener);
+  fsWatcher.close = () => {
+    watcherList.splice(watcherList.indexOf(fsWatcher), 1);
+    fsWatcher.close = () => { throw new Error('FSWatcher is already closed'); };
+  };
+  watcherList.push(fsWatcher);
+});
+
+fs.__triggerWatchEvent = (eventType, filename) => {
+  const directWatchers = watcherListByPath.get(filename) || [];
+  directWatchers.forEach(wtc => wtc.emit('change', eventType));
+  const dirPath = path.dirname(filename);
+  const dirWatchers = watcherListByPath.get(dirPath) || [];
+  dirWatchers.forEach(wtc => wtc.emit('change', eventType, path.relative(dirPath, filename)));
+};
+
 function getToNode(filepath) {
   // Ignore the drive for Windows paths.
   if (filepath.match(/^[a-zA-Z]:\\/)) {

packages/metro-bundler/src/node-haste/__tests__/DependencyGraph-test.js

@@ -130,7 +130,7 @@ describe('DependencyGraph', function() {
       },
       getTransformCacheKey: () => 'abcdef',
       reporter: require('../../lib/reporting').nullReporter,
-      watch: false,
+      watch: true,
     };
   });
 
@@ -3111,70 +3111,74 @@ describe('DependencyGraph', function() {
         filesystem.root['index.js'] = filesystem.root['index.js']
           .replace('require("dontWork")', '')
           .replace('require("wontWork")', '');
-        dgraph.processFileChange('change', root + '/index.js', mockStat);
-        return getOrderedDependenciesAsJSON(dgraph, '/root/index.js')
-          .then(deps => {
-            expect(deps).toEqual([
-              {
-                id: 'index',
-                path: '/root/index.js',
-                dependencies: [
-                  'shouldWork',
-                  'ember',
-                  'internalVendoredPackage',
-                  'anotherIndex',
-                ],
-                isAsset: false,
-                isJSON: false,
-                isPolyfill: false,
-                resolution: undefined,
-              },
-              {
-                id: 'shouldWork',
-                path: '/root/node_modules/react-haste/main.js',
-                dependencies: ['submodule'],
-                isAsset: false,
-                isJSON: false,
-                isPolyfill: false,
-                resolution: undefined,
-              },
-              {
-                id: 'submodule/main.js',
-                path: '/root/node_modules/react-haste/node_modules/submodule/main.js',
-                dependencies: [],
-                isAsset: false,
-                isJSON: false,
-                isPolyfill: false,
-                resolution: undefined,
-              },
-              {
-                id: 'ember/main.js',
-                path: '/root/node_modules/ember/main.js',
-                dependencies: [],
-                isAsset: false,
-                isJSON: false,
-                isPolyfill: false,
-                resolution: undefined,
-              },
-              {
-                id: 'internalVendoredPackage',
-                path: '/root/vendored_modules/a-vendored-package/main.js',
-                dependencies: [],
-                isAsset: false,
-                isJSON: false,
-                isPolyfill: false,
-                resolution: undefined,
-              },
-              {
-                id: 'anotherIndex',
-                path: '/anotherRoot/index.js',
-                dependencies: [],
-                isAsset: false,
-                isJSON: false,
-                isPolyfill: false,
-                resolution: undefined,
-              },
-            ]);
+        triggerWatchEvent('change', root + '/index.js');
+        return new Promise(resolve => {
+          dgraph.once('change', () => {
+            return resolve(getOrderedDependenciesAsJSON(dgraph, '/root/index.js')
+              .then(deps => {
+                expect(deps).toEqual([
+                  {
+                    id: 'index',
+                    path: '/root/index.js',
+                    dependencies: [
+                      'shouldWork',
+                      'ember',
+                      'internalVendoredPackage',
+                      'anotherIndex',
+                    ],
+                    isAsset: false,
+                    isJSON: false,
+                    isPolyfill: false,
+                    resolution: undefined,
+                  },
+                  {
+                    id: 'shouldWork',
+                    path: '/root/node_modules/react-haste/main.js',
+                    dependencies: ['submodule'],
+                    isAsset: false,
+                    isJSON: false,
+                    isPolyfill: false,
+                    resolution: undefined,
+                  },
+                  {
+                    id: 'submodule/main.js',
+                    path: '/root/node_modules/react-haste/node_modules/submodule/main.js',
+                    dependencies: [],
+                    isAsset: false,
+                    isJSON: false,
+                    isPolyfill: false,
+                    resolution: undefined,
+                  },
+                  {
+                    id: 'ember/main.js',
+                    path: '/root/node_modules/ember/main.js',
+                    dependencies: [],
+                    isAsset: false,
+                    isJSON: false,
+                    isPolyfill: false,
+                    resolution: undefined,
+                  },
+                  {
+                    id: 'internalVendoredPackage',
+                    path: '/root/vendored_modules/a-vendored-package/main.js',
+                    dependencies: [],
+                    isAsset: false,
+                    isJSON: false,
+                    isPolyfill: false,
+                    resolution: undefined,
+                  },
+                  {
+                    id: 'anotherIndex',
+                    path: '/anotherRoot/index.js',
+                    dependencies: [],
+                    isAsset: false,
+                    isJSON: false,
+                    isPolyfill: false,
+                    resolution: undefined,
+                  },
+                ]);
+              }));
+            });
           });
       });
     });
@@ -5455,4 +5459,8 @@ describe('DependencyGraph', function() {
   function setMockFileSystem(object) {
     return require('graceful-fs').__setMockFilesystem(object);
   }
+
+  function triggerWatchEvent(eventType, filename) {
+    return require('graceful-fs').__triggerWatchEvent(eventType, filename);
+  }
 });

packages/metro-bundler/src/node-haste/index.js

@@ -36,6 +36,7 @@ const {
   createActionStartEntry,
   log,
 } = require('../Logger');
+const {EventEmitter} = require('events');
 
 import type {Options as TransformOptions} from '../JSTransformer/worker/worker';
 import type GlobalTransformCache from '../lib/GlobalTransformCache';
@@ -72,7 +73,7 @@ type Options = {
   watch: boolean,
 };
 
-class DependencyGraph {
+class DependencyGraph extends EventEmitter {
   _opts: Options;
   _haste: JestHasteMap;
   _hasteFS: HasteFS;
@@ -84,6 +85,7 @@ class DependencyGraph {
   _loading: Promise<void>;
 
   constructor(opts: Options) {
+    super();
     this._opts = {...opts};
     this._helpers = new DependencyGraphHelpers(this._opts);
     this.load();
@@ -154,6 +156,7 @@ class DependencyGraph {
         eventsQueue.forEach(({type, filePath, stat}) =>
           this.processFileChange(type, filePath, stat)
         );
+        this.emit('change');
       });
 
       const buildingHasteMapLogEntry =