[test optimization][STV-59] Fix jest.mock for multi worker setups (#6729)

* fix listener

* add integration test

* add stdout check

Author: juan-fernandez

integration-tests/ci-visibility/jest-package-mock/non-dependency-mock-test-2.js

@@ -0,0 +1,11 @@
+'use strict'
+
+// This is to check that the actual package is loaded, to make sure
+// that the scenario is the same as the one that was failing.
+// Doing it in one of the test suites is enough, as the failure was
+// when calling jest.mock('some-package')
+const hello = jest.requireActual('some-package')
+
+test('hello function returns correct greeting', () => {
+  expect(hello()).toBe('Hello, world!')
+})

integration-tests/ci-visibility/jest-package-mock/non-dependency-mock-test-3.js

@@ -0,0 +1,7 @@
+'use strict'
+
+const hello = require('some-package')
+
+test('hello function returns correct greeting', () => {
+  expect(hello()).toBe('Hello, mocked world!')
+})

integration-tests/ci-visibility/jest-package-mock/non-dependency-mock-test-4.js

@@ -0,0 +1,7 @@
+'use strict'
+
+const hello = require('some-package')
+
+test('hello function returns correct greeting', () => {
+  expect(hello()).toBe('Hello, mocked world!')
+})

integration-tests/ci-visibility/jest-package-mock/non-dependency-mock-test-5.js

@@ -0,0 +1,7 @@
+'use strict'
+
+const hello = require('some-package')
+
+test('hello function returns correct greeting', () => {
+  expect(hello()).toBe('Hello, mocked world!')
+})

integration-tests/ci-visibility/jest-package-mock/non-dependency-mock-test-6.js

@@ -0,0 +1,7 @@
+'use strict'
+
+const hello = require('some-package')
+
+test('hello function returns correct greeting', () => {
+  expect(hello()).toBe('Hello, mocked world!')
+})

integration-tests/ci-visibility/jest-package-mock/non-dependency-mock-test.js

@@ -0,0 +1,7 @@
+'use strict'
+
+const hello = require('some-package')
+
+test('hello function returns correct greeting', () => {
+  expect(hello()).toBe('Hello, mocked world!')
+})

integration-tests/ci-visibility/jest-setup-files-after-env.js

@@ -0,0 +1,5 @@
+'use strict'
+
+jest.mock('some-package', () => {
+  return jest.fn(() => 'Hello, mocked world!')
+})

integration-tests/ci-visibility/packages/some-package/index.js

@@ -0,0 +1,5 @@
+'use strict'
+
+module.exports = function () {
+  return 'Hello, world!'
+}

integration-tests/ci-visibility/packages/some-package/package.json

@@ -0,0 +1,6 @@
+{
+  "name": "some-package",
+  "version": "1.0.0",
+  "main": "index.js",
+  "license": "MIT"
+}

integration-tests/ci-visibility/run-jest.js

@@ -9,7 +9,8 @@ const options = {
   testRegex: process.env.TESTS_TO_RUN ? new RegExp(process.env.TESTS_TO_RUN) : /test\/ci-visibility-test/,
   coverage: !!process.env.ENABLE_CODE_COVERAGE,
   runInBand: true,
-  shard: process.env.TEST_SHARD || undefined
+  shard: process.env.TEST_SHARD || undefined,
+  setupFilesAfterEnv: process.env.SETUP_FILES_AFTER_ENV ? process.env.SETUP_FILES_AFTER_ENV.split(',') : []
 }
 
 if (process.env.RUN_IN_PARALLEL) {