diff --git a/local-cli/__mocks__/fs.js b/local-cli/__mocks__/fs.js
index b2e2f9766..a3691e3f3 100644
--- a/local-cli/__mocks__/fs.js
+++ b/local-cli/__mocks__/fs.js
@@ -9,18 +9,21 @@
 
 'use strict';
 
-const fs = new (require('metro-memory-fs'))({cwd: process.cwd});
+const path = require('path');
+const MemoryFS = require('metro-memory-fs');
+let fs;
 
-function setMockFilesystem(object) {
-  fs.reset();
-  const root = process.platform === 'win32' ? 'c:\\' : '/';
+function setMockFilesystem(object, platform) {
+  reset(platform);
+  const root = platform === 'win32' ? 'c:\\' : '/';
   mockDir(root, {...object});
+  return root;
 }
 
 function mockDir(dirPath, desc) {
   for (const entName in desc) {
     const ent = desc[entName];
-    const entPath = require('path').join(dirPath, entName);
+    const entPath = path.join(dirPath, entName);
     if (typeof ent === 'string' || ent instanceof Buffer) {
       fs.writeFileSync(entPath, ent);
       continue;
@@ -37,7 +40,22 @@ function mockDir(dirPath, desc) {
   }
 }
 
-fs.__setMockFilesystem = setMockFilesystem;
-fs.mock = {clear: () => fs.reset()};
+function reset(platform) {
+  if (path.mock == null) {
+    throw new Error(
+      'to use this "fs" module mock, you must also mock the "path" module',
+    );
+  }
+  path.mock.reset(platform);
+  const cwd = () => (platform === 'win32' ? 'c:\\' : '/');
+  fs = new MemoryFS({platform, cwd});
+  Object.assign(mockFs, fs);
+}
 
-module.exports = fs;
+const mockFs = {};
+mockFs.__setMockFilesystem = setMockFilesystem;
+mockFs.mock = {clear: reset};
+
+reset('posix');
+
+module.exports = mockFs;
diff --git a/local-cli/__mocks__/path.js b/local-cli/__mocks__/path.js
new file mode 100644
index 000000000..884c3eac9
--- /dev/null
+++ b/local-cli/__mocks__/path.js
@@ -0,0 +1,20 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+'use strict';
+
+const mockPath = {};
+
+function reset(platform) {
+  Object.assign(mockPath, jest.requireActual('path')[platform]);
+}
+
+mockPath.mock = {reset};
+
+module.exports = mockPath;
diff --git a/local-cli/core/__fixtures__/android.js b/local-cli/core/__fixtures__/android.js
index 2d6447b87..07e1ee279 100644
--- a/local-cli/core/__fixtures__/android.js
+++ b/local-cli/core/__fixtures__/android.js
@@ -1,7 +1,14 @@
-/** @format */
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
 
 const fs = require.requireActual('fs');
-const path = require('path');
+const path = require.requireActual('path');
 
 const manifest = fs.readFileSync(
   path.join(__dirname, './files/AndroidManifest.xml'),
diff --git a/local-cli/core/__tests__/android/findAndroidAppFolder.spec.js b/local-cli/core/__tests__/android/findAndroidAppFolder.spec.js
index 00324c8e9..331dfe8e1 100644
--- a/local-cli/core/__tests__/android/findAndroidAppFolder.spec.js
+++ b/local-cli/core/__tests__/android/findAndroidAppFolder.spec.js
@@ -10,6 +10,7 @@
 
 'use strict';
 
+jest.mock('path');
 jest.mock('fs');
 
 const fs = require('fs');
diff --git a/local-cli/core/__tests__/android/findManifest.spec.js b/local-cli/core/__tests__/android/findManifest.spec.js
index 4bae9022d..242b20a74 100644
--- a/local-cli/core/__tests__/android/findManifest.spec.js
+++ b/local-cli/core/__tests__/android/findManifest.spec.js
@@ -10,6 +10,7 @@
 
 'use strict';
 
+jest.mock('path');
 jest.mock('fs');
 
 const findManifest = require('../../android/findManifest');
diff --git a/local-cli/core/__tests__/android/findPackageClassName.spec.js b/local-cli/core/__tests__/android/findPackageClassName.spec.js
index abf78b9df..5c15fd658 100644
--- a/local-cli/core/__tests__/android/findPackageClassName.spec.js
+++ b/local-cli/core/__tests__/android/findPackageClassName.spec.js
@@ -10,40 +10,49 @@
 
 'use strict';
 
+jest.mock('path');
 jest.mock('fs');
 
+const mocks = require('../../__fixtures__/android');
 const findPackageClassName = require('../../android/findPackageClassName');
 const fs = require('fs');
-const mocks = require('../../__fixtures__/android');
 
-describe('android::findPackageClassName', () => {
-  beforeAll(() => {
-    fs.__setMockFilesystem({
-      empty: {},
-      flatJava: {
-        android: mocks.valid,
-      },
-      flatKotlin: {
-        android: mocks.validKotlin,
-      },
+['posix', 'win32'].forEach(platform => {
+  let root;
+  describe(`android::findPackageClassName (${platform})`, () => {
+    beforeAll(() => {
+      root = fs.__setMockFilesystem(
+        {
+          empty: {},
+          flatJava: {
+            android: mocks.valid,
+          },
+          flatKotlin: {
+            android: mocks.validKotlin,
+          },
+        },
+        platform,
+      );
+    });
+
+    it('returns manifest content if file exists in the folder', () => {
+      expect(typeof findPackageClassName(root + 'flatJava')).toBe('string');
+    });
+
+    it('returns the name of the java class implementing ReactPackage', () => {
+      expect(findPackageClassName(root + 'flatJava')).toBe(
+        'SomeExampleJavaPackage',
+      );
+    });
+
+    it('returns the name of the kotlin class implementing ReactPackage', () => {
+      expect(findPackageClassName(root + 'flatKotlin')).toBe(
+        'SomeExampleKotlinPackage',
+      );
+    });
+
+    it('returns `null` if there are no matches', () => {
+      expect(findPackageClassName(root + 'empty')).toBeNull();
     });
   });
-
-  it('returns manifest content if file exists in the folder', () => {
-    expect(typeof findPackageClassName('/flatJava')).toBe('string');
-  });
-
-  it('returns the name of the java class implementing ReactPackage', () => {
-    expect(findPackageClassName('/flatJava')).toBe('SomeExampleJavaPackage');
-  });
-
-  it('returns the name of the kotlin class implementing ReactPackage', () => {
-    expect(findPackageClassName('/flatKotlin')).toBe(
-      'SomeExampleKotlinPackage',
-    );
-  });
-
-  it('returns `null` if there are no matches', () => {
-    expect(findPackageClassName('/empty')).toBeNull();
-  });
 });
diff --git a/local-cli/core/__tests__/android/getDependencyConfig.spec.js b/local-cli/core/__tests__/android/getDependencyConfig.spec.js
index ddba5bf4f..7a43db319 100644
--- a/local-cli/core/__tests__/android/getDependencyConfig.spec.js
+++ b/local-cli/core/__tests__/android/getDependencyConfig.spec.js
@@ -10,6 +10,7 @@
 
 'use strict';
 
+jest.mock('path');
 jest.mock('fs');
 
 const getDependencyConfig = require('../../android').dependencyConfig;
diff --git a/local-cli/core/__tests__/android/getProjectConfig.spec.js b/local-cli/core/__tests__/android/getProjectConfig.spec.js
index 356f3455b..863138c95 100644
--- a/local-cli/core/__tests__/android/getProjectConfig.spec.js
+++ b/local-cli/core/__tests__/android/getProjectConfig.spec.js
@@ -10,6 +10,7 @@
 
 'use strict';
 
+jest.mock('path');
 jest.mock('fs');
 
 const getProjectConfig = require('../../android').projectConfig;
diff --git a/local-cli/core/__tests__/android/readManifest.spec.js b/local-cli/core/__tests__/android/readManifest.spec.js
index bd733af16..2b8f41e4f 100644
--- a/local-cli/core/__tests__/android/readManifest.spec.js
+++ b/local-cli/core/__tests__/android/readManifest.spec.js
@@ -10,6 +10,7 @@
 
 'use strict';
 
+jest.mock('path');
 jest.mock('fs');
 
 const findManifest = require('../../android/findManifest');
diff --git a/local-cli/core/__tests__/findAssets.spec.js b/local-cli/core/__tests__/findAssets.spec.js
index a2d65df46..cf880b23d 100644
--- a/local-cli/core/__tests__/findAssets.spec.js
+++ b/local-cli/core/__tests__/findAssets.spec.js
@@ -10,6 +10,7 @@
 
 'use strict';
 
+jest.mock('path');
 jest.mock('fs');
 
 const findAssets = require('../findAssets');
diff --git a/local-cli/core/__tests__/ios/findPodfilePath.spec.js b/local-cli/core/__tests__/ios/findPodfilePath.spec.js
index 55af185b2..227d24512 100644
--- a/local-cli/core/__tests__/ios/findPodfilePath.spec.js
+++ b/local-cli/core/__tests__/ios/findPodfilePath.spec.js
@@ -10,6 +10,7 @@
 
 'use strict';
 
+jest.mock('path');
 jest.mock('fs');
 
 const findPodfilePath = require('../../ios/findPodfilePath');
diff --git a/local-cli/core/__tests__/ios/findPodspecName.spec.js b/local-cli/core/__tests__/ios/findPodspecName.spec.js
index c499b0512..14d73cd7d 100644
--- a/local-cli/core/__tests__/ios/findPodspecName.spec.js
+++ b/local-cli/core/__tests__/ios/findPodspecName.spec.js
@@ -10,6 +10,7 @@
 
 'use strict';
 
+jest.mock('path');
 jest.mock('fs');
 
 const findPodspecName = require('../../ios/findPodspecName');
diff --git a/local-cli/core/__tests__/ios/findProject.spec.js b/local-cli/core/__tests__/ios/findProject.spec.js
index d792f72db..0083e9bd0 100644
--- a/local-cli/core/__tests__/ios/findProject.spec.js
+++ b/local-cli/core/__tests__/ios/findProject.spec.js
@@ -10,6 +10,7 @@
 
 'use strict';
 
+jest.mock('path');
 jest.mock('fs');
 
 const findProject = require('../../ios/findProject');
diff --git a/local-cli/core/__tests__/ios/getProjectConfig.spec.js b/local-cli/core/__tests__/ios/getProjectConfig.spec.js
index 0f9b25e22..d1af61e4b 100644
--- a/local-cli/core/__tests__/ios/getProjectConfig.spec.js
+++ b/local-cli/core/__tests__/ios/getProjectConfig.spec.js
@@ -10,6 +10,7 @@
 
 'use strict';
 
+jest.mock('path');
 jest.mock('fs');
 
 const getProjectConfig = require('../../ios').projectConfig;
diff --git a/local-cli/link/__tests__/ios/writePlist.spec.js b/local-cli/link/__tests__/ios/writePlist.spec.js
index b87627b1d..1bdb4ed82 100644
--- a/local-cli/link/__tests__/ios/writePlist.spec.js
+++ b/local-cli/link/__tests__/ios/writePlist.spec.js
@@ -10,6 +10,7 @@
 
 'use strict';
 
+jest.mock('path');
 jest.mock('fs');
 
 let plistPath = null;
diff --git a/local-cli/util/__tests__/findSymlinkedModules-test.js b/local-cli/util/__tests__/findSymlinkedModules-test.js
index 02337f1a2..fbdfd7463 100644
--- a/local-cli/util/__tests__/findSymlinkedModules-test.js
+++ b/local-cli/util/__tests__/findSymlinkedModules-test.js
@@ -8,6 +8,7 @@
  * @emails oncall+javascript_foundation
  */
 
+jest.mock('path');
 jest.mock('fs');
 
 const fs = require('fs');