packager: DependencyGraph-test: require extractDependencies only once

Reviewed By: davidaurelio

Differential Revision: D4182071

fbshipit-source-id: 622cb3e011b67c2a7df0c6308fbcb7a9ea1ebb96

packager/react-packager/src/node-haste/__tests__/DependencyGraph-test.js

@@ -111,6 +111,11 @@ jest.mock('jest-haste-map/build/crawlers/node', () => {
 
 const mocksPattern = /(?:[\\/]|^)__mocks__[\\/]([^\/]+)\.js$/;
 
+// This doesn't have state, and it's huge (Babel) so it's much faster to
+// require it only once.
+const extractDependencies = require('../../JSTransformer/worker/extract-dependencies');
+jest.mock('../../JSTransformer/worker/extract-dependencies', () => extractDependencies);
+
 jasmine.DEFAULT_TIMEOUT_INTERVAL = 10000;
 
 const path = require('path');
@@ -122,7 +127,6 @@ beforeEach(() => {
 
 describe('DependencyGraph', function() {
   let Module;
-  let extractDependencies;
   let defaults;
 
   function getOrderedDependenciesAsJSON(dgraph, entryPath, platform, recursive = true) {
@@ -193,8 +197,6 @@ describe('DependencyGraph', function() {
     Cache.prototype.end = jest.genMockFn();
 
     const transformCacheKey = 'abcdef';
-    extractDependencies =
-      require('../../JSTransformer/worker/extract-dependencies');
     defaults = {
       assetExts: ['png', 'jpg'],
       cache: new Cache(),
@@ -2744,7 +2746,6 @@ describe('DependencyGraph', function() {
       jest.resetModules();
       jest.mock('path', () => path.win32);
       DependencyGraph = require('../index');
-      extractDependencies = require('../../JSTransformer/worker/extract-dependencies');
     });
 
     afterEach(function() {