diff --git a/packages/metro-bundler/src/lib/__tests__/GlobalTransformCache-test.js b/packages/metro-bundler/src/lib/__tests__/GlobalTransformCache-test.js
index 94039e8b..ec077d1e 100644
--- a/packages/metro-bundler/src/lib/__tests__/GlobalTransformCache-test.js
+++ b/packages/metro-bundler/src/lib/__tests__/GlobalTransformCache-test.js
@@ -12,8 +12,8 @@
 jest.disableAutomock();
 jest.useRealTimers();
 
-const fetchMock = jest.fn();
-jest.mock('node-fetch', () => fetchMock);
+const mockFetch = jest.fn();
+jest.mock('node-fetch', () => mockFetch);
 
 const {URIBasedGlobalTransformCache} = require('../GlobalTransformCache');
 const FetchError = require('node-fetch/lib/fetch-error');
@@ -82,19 +82,19 @@ describe('GlobalTransformCache', () => {
     });
 
     beforeEach(() => {
-      fetchMock.mockReset();
+      mockFetch.mockReset();
     });
 
     it('fetches result', async () => {
-      fetchMock.mockImplementation(defaultFetchMockImpl);
+      mockFetch.mockImplementation(defaultFetchMockImpl);
       const result = await URIBasedGlobalTransformCache
         .fetchResultFromURI('http://globalcache.com/foo');
       expect(result).toMatchSnapshot();
     });
 
     it('retries once on timeout', async () => {
-      fetchMock.mockImplementation(async uri => {
-        fetchMock.mockImplementation(defaultFetchMockImpl);
+      mockFetch.mockImplementation(async uri => {
+        mockFetch.mockImplementation(defaultFetchMockImpl);
         throw new FetchError('timeout!', 'request-timeout');
       });
       const result = await URIBasedGlobalTransformCache
diff --git a/packages/metro-bundler/src/lib/__tests__/TransformCache-test.js b/packages/metro-bundler/src/lib/__tests__/TransformCache-test.js
index 9f34c483..e9bab8eb 100644
--- a/packages/metro-bundler/src/lib/__tests__/TransformCache-test.js
+++ b/packages/metro-bundler/src/lib/__tests__/TransformCache-test.js
@@ -21,14 +21,14 @@ const imurmurhash = require('imurmurhash');
 const crypto = require('crypto');
 const jsonStableStringify = require('json-stable-stringify');
 
-const memoryFS = new Map();
+const mockFS = new Map();
 
 jest.mock('fs', () => ({
   readFileSync(filePath) {
-    return memoryFS.get(filePath);
+    return mockFS.get(filePath);
   },
   unlinkSync(filePath) {
-    memoryFS.delete(filePath);
+    mockFS.delete(filePath);
   },
   readdirSync(dirPath) {
     // Not required for it to work.
@@ -38,7 +38,7 @@ jest.mock('fs', () => ({
 
 jest.mock('write-file-atomic', () => ({
   sync(filePath, data) {
-    memoryFS.set(filePath, data.toString());
+    mockFS.set(filePath, data.toString());
   },
 }));
 
@@ -56,7 +56,7 @@ describe('TransformCache', () => {
 
   beforeEach(() => {
     jest.resetModules();
-    memoryFS.clear();
+    mockFS.clear();
     TransformCache = require('../TransformCache');
   });
 
diff --git a/packages/metro-bundler/src/node-haste/__tests__/DependencyGraph-test.js b/packages/metro-bundler/src/node-haste/__tests__/DependencyGraph-test.js
index f55ee0a9..489be4ba 100644
--- a/packages/metro-bundler/src/node-haste/__tests__/DependencyGraph-test.js
+++ b/packages/metro-bundler/src/node-haste/__tests__/DependencyGraph-test.js
@@ -19,9 +19,10 @@ jest
   ;
 
 // 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);
+// require it only once. The variable name is prefixed with "mock" as an escape-hatch
+// for babel-plugin-jest-hoist.
+const mockExtractDependencies = require('../../JSTransformer/worker/extract-dependencies');
+jest.mock('../../JSTransformer/worker/extract-dependencies', () => mockExtractDependencies);
 
 jasmine.DEFAULT_TIMEOUT_INTERVAL = 10000;
 
@@ -119,7 +120,7 @@ describe('DependencyGraph', function() {
         return new Promise(resolve => {
           let deps = {dependencies: [], dependencyOffsets: []};
           if (!module.path.endsWith('.json')) {
-            deps = extractDependencies(sourceCode);
+            deps = mockExtractDependencies(sourceCode);
           }
           resolve({...deps, code: sourceCode});
         });