feat(jest-runtime): calling jest.resetModules function will clear req…

…uire cache

CHANGELOG.md

@@ -1,7 +1,7 @@
 ## main
 
 ### Features
-
+- `[jest-runtime]` Calling jest.resetModules function will clear require cache ([#12531](https://github.com/facebook/jest/pull/12531))
 - `[babel-jest]` Export `createTransformer` function ([#12399](https://github.com/facebook/jest/pull/12399))
 - `[expect]` Expose `AsymmetricMatchers`, `MatcherFunction` and `MatcherFunctionWithState` interfaces ([#12363](https://github.com/facebook/jest/pull/12363), [#12376](https://github.com/facebook/jest/pull/12376))
 - `[jest-circus, jest-jasmine2]` Allowed classes and functions as `describe` and `it`/`test` names ([#12484](https://github.com/facebook/jest/pull/12484))

e2e/__tests__/clearRequireCache.test.ts

@@ -0,0 +1,6 @@
+import runJest from '../runJest';
+
+test('clear require cache', () => {
+  const {exitCode} = runJest('clear-require-cache');
+  expect(exitCode).toBe(0);
+});

e2e/clear-require-cache/package.json

@@ -0,0 +1,5 @@
+{
+  "jest": {
+    "testEnvironment": "node"
+  }
+}

e2e/clear-require-cache/test.js

@@ -0,0 +1,25 @@
+const fs = require('fs');
+const path = require('path');
+
+const asboulteTestHelperFile = path.resolve(__dirname, './testHelper.js');
+
+beforeAll(() => {
+  fs.writeFileSync(asboulteTestHelperFile, 'module.exports = 1;\n');
+});
+
+test('value is 1', () => {
+  const value = require('./testHelper');
+  expect(value).toBe(1);
+});
+
+test('value is 1 after file change', () => {
+  fs.writeFileSync(asboulteTestHelperFile, 'module.exports = 2;\n');
+  const value = require('./testHelper');
+  expect(value).toBe(1);
+});
+
+test('value is 2', () => {
+  jest.resetModules();
+  const value = require('./testHelper');
+  expect(value).toBe(2);
+});

e2e/clear-require-cache/testHelper.js

@@ -0,0 +1 @@
+module.exports = 2;

packages/jest-runtime/src/index.ts

@@ -1141,6 +1141,8 @@ export default class Runtime {
     this._esmoduleRegistry.clear();
     this._cjsNamedExports.clear();
     this._moduleMockRegistry.clear();
+    this._cacheFS.clear();
+    this._fileTransforms.clear();
 
     if (this._environment) {
       if (this._environment.global) {