diff --git a/packages/metro-file-map/src/__tests__/createStaticCrawler-test.js b/packages/metro-file-map/src/__tests__/createStaticCrawler-test.js
index 3f12b6c5bc..c49179a3f5 100644
--- a/packages/metro-file-map/src/__tests__/createStaticCrawler-test.js
+++ b/packages/metro-file-map/src/__tests__/createStaticCrawler-test.js
@@ -79,8 +79,8 @@ function createFileMap(
 describe('createStaticCrawler', () => {
   test('builds a FileSystem from the supplied listing', async () => {
     const {fileMap} = createFileMap([
-      {path: 'src/index.js'},
-      {path: 'src/nested/other.js'},
+      {path: path.join('src', 'index.js')},
+      {path: path.join('src', 'nested', 'other.js')},
       {path: p('absolute.js')},
     ]);
 
@@ -98,10 +98,10 @@ describe('createStaticCrawler', () => {
 
   test('populates HastePlugin from per-file plugin data', async () => {
     const {fileMap, hastePlugin} = createFileMap([
-      {path: 'src/Thing.js', pluginData: {haste: 'Thing'}},
-      {path: 'src/Thing.ios.js', pluginData: {haste: 'Thing'}},
-      {path: 'src/NoHaste.js'},
-      {path: 'pkg/package.json', pluginData: {haste: 'HastePkg'}},
+      {path: path.join('src', 'Thing.js'), pluginData: {haste: 'Thing'}},
+      {path: path.join('src', 'Thing.ios.js'), pluginData: {haste: 'Thing'}},
+      {path: path.join('src', 'NoHaste.js')},
+      {path: path.join('pkg', 'package.json'), pluginData: {haste: 'HastePkg'}},
     ]);
 
     await fileMap.build();
@@ -122,7 +122,7 @@ describe('createStaticCrawler', () => {
   test('does not process any file contents', async () => {
     const processBatch = jest.spyOn(FileProcessor.prototype, 'processBatch');
     const {fileMap} = createFileMap([
-      {path: 'src/index.js', pluginData: {haste: 'Index'}},
+      {path: path.join('src', 'index.js'), pluginData: {haste: 'Index'}},
     ]);
 
     await fileMap.build();
@@ -137,7 +137,10 @@ describe('createStaticCrawler', () => {
     // data supplied here is taken at face value. Callers must filter for
     // themselves.
     const {fileMap, hastePlugin} = createFileMap([
-      {path: 'node_modules/pkg/Thing.js', pluginData: {haste: 'Thing'}},
+      {
+        path: path.join('node_modules', 'pkg', 'Thing.js'),
+        pluginData: {haste: 'Thing'},
+      },
     ]);
 
     await fileMap.build();
@@ -152,7 +155,9 @@ describe('createStaticCrawler', () => {
     // more than one pass - a single-use iterable would report nothing the
     // second time.
     const staticFactory = createStaticCrawler({
-      files: [{path: 'src/Thing.js', pluginData: {haste: 'Thing'}}],
+      files: [
+        {path: path.join('src', 'Thing.js'), pluginData: {haste: 'Thing'}},
+      ],
     });
     let inner: ?Crawler = null;
     let seenOptions: ?CrawlerOptions = null;
@@ -181,7 +186,7 @@ describe('createStaticCrawler', () => {
   });
 
   test('end() is safe when not watching', async () => {
-    const {fileMap} = createFileMap([{path: 'src/index.js'}]);
+    const {fileMap} = createFileMap([{path: path.join('src', 'index.js')}]);
     await fileMap.build();
     await expect(fileMap.end()).resolves.toBeUndefined();
   });
diff --git a/packages/metro-resolver/src/__tests__/scheme-resolvers-test.js b/packages/metro-resolver/src/__tests__/scheme-resolvers-test.js
index 411c4701b0..f8ede811bc 100644
--- a/packages/metro-resolver/src/__tests__/scheme-resolvers-test.js
+++ b/packages/metro-resolver/src/__tests__/scheme-resolvers-test.js
@@ -18,13 +18,13 @@ import type {
   ResolutionContext,
 } from '../index';
 
-import {createResolutionContext} from './utils';
+import {createResolutionContext, posixToSystemPath as p} from './utils';
 
 const Resolver = require('../index');
 
 const fileMap = {
-  '/root/project/foo.js': '',
-  '/root/project/bar.js': '',
+  [p('/root/project/foo.js')]: '',
+  [p('/root/project/bar.js')]: '',
 };
 
 function createContext(
@@ -32,7 +32,7 @@ function createContext(
 ): ResolutionContext {
   return {
     ...createResolutionContext(fileMap),
-    originModulePath: '/root/project/foo.js',
+    originModulePath: p('/root/project/foo.js'),
     schemeResolvers,
   };
 }
@@ -58,7 +58,7 @@ function makeCapturingResolver(resolution: Resolution): {
 test('invokes a registered scheme resolver with the full specifier', () => {
   const resolution: Resolution = {
     type: 'sourceFile',
-    filePath: '/resolved/by/scheme.js',
+    filePath: p('/resolved/by/scheme.js'),
   };
   const {resolver, calls} = makeCapturingResolver(resolution);
   const context = createContext({test: resolver});
@@ -81,7 +81,7 @@ test('scheme resolver can delegate back to default resolution', () => {
 
   expect(Resolver.resolve(context, 'test:anything', null)).toEqual({
     type: 'sourceFile',
-    filePath: '/root/project/bar.js',
+    filePath: p('/root/project/bar.js'),
   });
 });
 
@@ -127,7 +127,7 @@ test('an unregistered scheme still resolves if another strategy succeeds', () =>
   const context = {
     ...createContext({test: resolver}),
     resolveHasteModule: (name: string) =>
-      name === 'other:module' ? '/root/project/bar.js' : null,
+      name === 'other:module' ? p('/root/project/bar.js') : null,
   };
 
   // The deprecated backwards-compatibility path: a scheme-like specifier with
@@ -135,7 +135,7 @@ test('an unregistered scheme still resolves if another strategy succeeds', () =>
   // rather than failing on the scheme.
   expect(Resolver.resolve(context, 'other:module', null)).toEqual({
     type: 'sourceFile',
-    filePath: '/root/project/bar.js',
+    filePath: p('/root/project/bar.js'),
   });
   expect(calls).toHaveLength(0);
 });
@@ -148,7 +148,7 @@ test('relative specifiers are resolved before scheme dispatch', () => {
   // mistaken for a scheme, even when scheme resolvers are registered.
   expect(Resolver.resolve(context, './bar', null)).toEqual({
     type: 'sourceFile',
-    filePath: '/root/project/bar.js',
+    filePath: p('/root/project/bar.js'),
   });
   expect(calls).toHaveLength(0);
 });
diff --git a/packages/metro/src/lib/__tests__/metroSchemeResolver-test.js b/packages/metro/src/lib/__tests__/metroSchemeResolver-test.js
index 725ff72139..3cad290c8f 100644
--- a/packages/metro/src/lib/__tests__/metroSchemeResolver-test.js
+++ b/packages/metro/src/lib/__tests__/metroSchemeResolver-test.js
@@ -16,6 +16,11 @@ import type {CustomResolutionContext, CustomResolver} from 'metro-resolver';
 import metroSchemeResolver from '../metroSchemeResolver';
 import {createResolutionContext} from 'metro-resolver/private/__tests__/utils';
 
+const p: (posixPath: string) => string =
+  process.platform === 'win32'
+    ? posixPath => posixPath.replace(/^\//, 'C:\\').replaceAll('/', '\\')
+    : posixPath => posixPath;
+
 type Call = {
   originModulePath: string,
   specifier: string,
@@ -25,7 +30,7 @@ type Call = {
 function makeContext(resolveRequest: CustomResolver): CustomResolutionContext {
   return {
     ...createResolutionContext({}),
-    originModulePath: '/root/project/foo.js',
+    originModulePath: p('/root/project/foo.js'),
     resolveRequest,
   };
 }
@@ -43,7 +48,7 @@ function makeCapturingResolveRequest(): {
       specifier,
       platform,
     });
-    return {type: 'sourceFile', filePath: '/resolved.js'};
+    return {type: 'sourceFile', filePath: p('/resolved.js')};
   };
   return {resolveRequest, calls};
 }
@@ -54,14 +59,14 @@ test('resolves metro:babel-runtime to @babel/runtime via package self resolution
 
   expect(metroSchemeResolver(context, 'metro:babel-runtime', 'ios')).toEqual({
     type: 'sourceFile',
-    filePath: '/resolved.js',
+    filePath: p('/resolved.js'),
   });
   expect(calls).toHaveLength(1);
   expect(calls[0].specifier).toBe('@babel/runtime');
   expect(calls[0].platform).toBe('ios');
   // The origin is @babel/runtime's own package.json (statically resolved), so
   // Metro resolves the subpath as a package self-reference via its `exports`.
-  expect(calls[0].originModulePath).toContain('@babel/runtime');
+  expect(calls[0].originModulePath).toContain(p('@babel/runtime'));
   expect(calls[0].originModulePath.endsWith('package.json')).toBe(true);
 });
 
diff --git a/packages/metro/src/lib/metroSchemeResolver.js b/packages/metro/src/lib/metroSchemeResolver.js
index 7b44ad03bf..590256bd5e 100644
--- a/packages/metro/src/lib/metroSchemeResolver.js
+++ b/packages/metro/src/lib/metroSchemeResolver.js
@@ -38,7 +38,7 @@ function getBabelRuntimePackageJsonPath(): string {
  * Resolver used for Metro's own `metro:` URI scheme, currently handling only
  * metro:babel-runtime and subpaths.
  */
-const metroSchemeResolver: CustomResolver = (context, specifier, platform) => {
+export default ((context, specifier, platform) => {
   const {protocol, pathname} = new URL(specifier);
 
   // Maps `metro:babel-runtime` (and subpaths, e.g.
@@ -61,6 +61,4 @@ const metroSchemeResolver: CustomResolver = (context, specifier, platform) => {
   }
 
   throw new Error(`Unsupported '${protocol}' pathname: ${pathname}`);
-};
-
-export default metroSchemeResolver;
+}) as CustomResolver;