Test require.context

packages/metro-runtime/src/polyfills/__tests__/require-test.js

@@ -478,6 +478,13 @@ describe('require', () => {
       expect(fn.mock.calls.length).toBe(1);
     });
 
+    it('throws when using require.context directly', () => {
+      createModuleSystem(moduleSystem, false, '');
+      expect(() => moduleSystem.__r.context('foobar')).toThrow(
+        'The experimental Metro feature `require.context` is not enabled in your project.',
+      );
+    });
+
     it('throws an error when trying to require an unknown module', () => {
       createModuleSystem(moduleSystem, false, '');
 

packages/metro-runtime/src/polyfills/require.js

@@ -281,7 +281,7 @@ metroRequire.importAll = metroImportAll;
 // The `require.context()` syntax is never executed in the runtime because it is converted
 // to `require()` in `metro/src/ModuleGraph/worker/collectDependencies.js` after collecting
 // dependencies. If the feature flag is not enabled then the conversion never takes place and this error is thrown (development only).
-metroRequire.context = () => {
+metroRequire.context = function fallbackRequireContext() {
   if (__DEV__) {
     throw new Error(
       `The experimental Metro feature \`require.context\` is not enabled in your project.\nThis can be enabled by setting the \`transformer.unstable_allowRequireContext\` property to \`true\` in your Metro configuration.`,

packages/metro/src/DeltaBundler/__tests__/DeltaCalculator-test.js

@@ -36,6 +36,7 @@ describe('DeltaCalculator', () => {
   let fileWatcher;
 
   const options = {
+    unstable_allowRequireContext: true,
     experimentalImportBundleSupport: false,
     onProgress: null,
     resolve: (from: string, to: string) => {