feat(in place): support in place mutation (#2706)

Add `--inPlace` flag (or equivalent in stryker.conf.json file). When `inPlace` is `true` (default is `false`), mutations are written "in place", overriding the user's own files. This way, Stryker can support more exotic project configurations, where even copying to a temp directory breaks the test run. For example, when a project relies on [app-root-path](https://www.npmjs.com/package/app-root-path) or uses the [`NODE_PATH`](https://nodejs.org/dist/latest-v14.x/docs/api/modules.html#modules_loading_from_the_global_folders) environment variable.

Support for `--inPlace` added in the `Sandbox` class. For each file that changes, it writes a backup to a ".stryker-tmp/backup123" directory. After mutation testing completes, the backup files are recovered from the backup directory. 

Stryker tries its best to recover the backup files and when the process exits unexpectantly, for example, using `CTRL+C` or by closing the window. This behavior is a best-effort since Stryker can't do anything for you when you kill it from the task manager or with `kill -9`.

.vscode/launch.json

@@ -4,71 +4,6 @@
   // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
   "version": "0.2.0",
   "configurations": [
-    {
-      "type": "node",
-      "request": "launch",
-      "name": "Launch Program",
-      "program": "${file}",
-      "skipFiles": [
-        "<node_internals>/**"
-      ]
-    },
-    {
-      "type": "node",
-      "request": "launch",
-      "name": "Stryker unit tests",
-      "program": "${workspaceRoot}/node_modules/mocha/bin/_mocha",
-      "args": [
-        "--timeout",
-        "999999",
-        "--colors",
-        "${workspaceRoot}/packages/stryker/test/helpers",
-        "${workspaceRoot}/packages/stryker/test/unit/**/*.js"
-      ],
-      "internalConsoleOptions": "openOnSessionStart"
-    },
-    {
-      "type": "node",
-      "request": "launch",
-      "name": "Stryker-mocha-framework unit tests",
-      "program": "${workspaceRoot}/node_modules/mocha/bin/_mocha",
-      "args": [
-        "--timeout",
-        "999999",
-        "--colors",
-        "${workspaceRoot}/packages/stryker-mocha-framework/test/helpers",
-        "${workspaceRoot}/packages/stryker-mocha-framework/test/unit/**/*.js"
-      ],
-      "internalConsoleOptions": "openOnSessionStart"
-    },
-    {
-      "type": "node",
-      "request": "launch",
-      "name": "babel-transpiler unit tests",
-      "program": "${workspaceRoot}/node_modules/mocha/bin/_mocha",
-      "args": [
-        "--timeout",
-        "999999",
-        "--colors",
-        "${workspaceRoot}/packages/stryker-babel-transpiler/test/helpers",
-        "${workspaceRoot}/packages/stryker-babel-transpiler/test/unit/**/*.js"
-      ],
-      "internalConsoleOptions": "openOnSessionStart"
-    },
-    {
-      "type": "node",
-      "request": "launch",
-      "name": "javascript-mutator unit tests",
-      "program": "${workspaceRoot}/node_modules/mocha/bin/_mocha",
-      "args": [
-        "--timeout",
-        "999999",
-        "--colors",
-        "${workspaceRoot}/packages/stryker-javascript-mutator/test/helpers",
-        "${workspaceRoot}/packages/stryker-javascript-mutator/test/unit/**/*.js"
-      ],
-      "internalConsoleOptions": "openOnSessionStart"
-    },
     {
       "type": "node",
       "request": "attach",

docs/configuration.md

@@ -145,6 +145,19 @@ When using the config file you can provide an array with `string`s
 
 You can *ignore* files by adding an exclamation mark (`!`) at the start of an expression.
 
+### `inPlace` [`boolean`]
+
+Default: `false`<br />
+Command line: `--inPlace`<br />
+Config file: `"inPlace": true`<br />
+
+Determines whether or not Stryker should mutate your files in place. 
+Note: mutating your files in place is generally not needed for mutation testing, unless you have a dependency in your project that is really dependent on the file locations (like "app-root-path" for example).
+
+When `true`, Stryker will override your files, but it will keep a copy of the originals in the temp directory (using `tempDirName`) and it will place the originals back after it is done.
+
+When `false` (default) Stryker will work in the copy of your code inside the temp directory.
+
 ### `logLevel` [`string`]
 
 Default: `info`<br />

e2e/test/in-place/.mocharc.jsonc

@@ -0,0 +1,4 @@
+{
+    "require": "./test/helpers/testSetup.js",
+    "spec": ["test/unit/*.js"]
+}

e2e/test/in-place/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "in-place",
+  "version": "0.0.0",
+  "private": true,
+  "description": "A module to perform an integration test",
+  "main": "index.js",
+  "scripts": {
+    "pretest": "rimraf \"reports\"",
+    "test": "mocha --no-config --require ../../tasks/ts-node-register.js --no-timeout verify/*.ts",
+    "test:unit": "mocha",
+    "test:mutation": "stryker run"
+  },
+  "author": "",
+  "license": "ISC"
+}

e2e/test/in-place/src/Add.js

@@ -0,0 +1,24 @@
+module.exports.add = function(num1, num2) {
+  return num1 + num2;
+};
+
+module.exports.addOne = function(number) {
+  number++;
+  return number;
+};
+
+module.exports.negate = function(number) {
+  return -number;
+};
+
+module.exports.notCovered = function(number) {
+  return number > 10;
+};
+
+module.exports.isNegativeNumber = function(number) {
+  var isNegative = false;
+  if(number < 0){
+    isNegative = true;
+  }
+  return isNegative;
+};

e2e/test/in-place/stryker.conf.json

@@ -0,0 +1,15 @@
+{
+  "$schema": "../../node_modules/@stryker-mutator/core/schema/stryker-schema.json",
+  "testRunner": "mocha",
+  "concurrency": 2,
+  "coverageAnalysis": "perTest",
+  "reporters": [
+    "clear-text",
+    "html",
+    "event-recorder"
+  ],
+  "plugins": [
+    "@stryker-mutator/mocha-runner"
+  ],
+  "inPlace": true
+}

e2e/test/in-place/test/helpers/testSetup.js

@@ -0,0 +1,5 @@
+exports.mochaHooks = {
+  beforeAll() {
+    global.expect = require('chai').expect;
+  }
+}

e2e/test/in-place/test/unit/Add.spec.js

@@ -0,0 +1,52 @@
+var addModule = require('../../src/Add');
+var add = addModule.add;
+var addOne = addModule.addOne;
+var isNegativeNumber = addModule.isNegativeNumber;
+var negate = addModule.negate;
+var notCovered = addModule.notCovered;
+
+describe('Add', function() {
+  it('should be able to add two numbers', function() {
+    var num1 = 2;
+    var num2 = 5;
+    var expected = num1 + num2;
+
+    var actual = add(num1, num2);
+
+    expect(actual).to.be.equal(expected);
+  });
+
+  it('should be able 1 to a number', function() {
+    var number = 2;
+    var expected = 3;
+
+    var actual = addOne(number);
+
+    expect(actual).to.be.equal(expected);
+  });
+
+  it('should be able negate a number', function() {
+    var number = 2;
+    var expected = -2;
+
+    var actual = negate(number);
+
+    expect(actual).to.be.equal(expected);
+  });
+
+  it('should be able to recognize a negative number', function() {
+    var number = -2;
+
+    var isNegative = isNegativeNumber(number);
+
+    expect(isNegative).to.be.true;
+  });
+
+  it('should be able to recognize that 0 is not a negative number', function() {
+    var number = 0;
+
+    var isNegative = isNegativeNumber(number);
+
+    expect(isNegative).to.be.false;
+  });
+});

e2e/test/in-place/test/unit/Wait.spec.js

@@ -0,0 +1,13 @@
+const { existsSync } = require('fs');
+const path = require('path');
+
+describe('wait', () =>{
+  it('should wait until `.lock` is removed', async () => {
+    while(existsSync(path.resolve(__dirname, '..', '..', '.lock'))){
+      await sleep(10);
+    }
+  });
+})
+async function sleep(n) {
+  return new Promise(res => setTimeout(res, n));
+}

e2e/test/in-place/verify/verify.ts

@@ -0,0 +1,69 @@
+import { expectMetrics } from '../../../helpers';
+import { promises as fsPromises } from 'fs';
+import chai from 'chai';
+import execa from 'execa';
+import rimraf from 'rimraf';
+import path from 'path';
+import { promisify } from 'util';
+import { it } from 'mocha';
+import chaiAsPromised from 'chai-as-promised';
+
+chai.use(chaiAsPromised);
+const expect = chai.expect;
+
+const rm = promisify(rimraf);
+
+const rootResolve: typeof path.resolve = path.resolve.bind(path, __dirname, '..');
+
+describe('in place', () => {
+
+  let originalAddJSContent: string;
+
+
+  function readAddJS(): Promise<string> {
+    return fsPromises.readFile(rootResolve('src', 'Add.js'), 'utf-8');
+  }
+
+  before(async () => {
+    originalAddJSContent = await readAddJS();
+  })
+
+
+  afterEach(async () => {
+    await rm(rootResolve('reports'));
+    await rm(rootResolve('.lock'));
+  })
+
+  it('should reset files after a successful run', async () => {
+    execa.sync('stryker', ['run']);
+    const addJSContent = await fsPromises.readFile(rootResolve('src', 'Add.js'), 'utf-8');
+    expect(addJSContent).eq(originalAddJSContent);
+  });
+
+  it('should report correct score', async () => {
+    execa.sync('stryker', ['run']);
+    await expectMetrics({ mutationScore: 73.68 });
+  });
+
+  it('should also reset the files if Stryker exits unexpectedly', async () => {
+    // Arrange
+    let addJSMutatedContent: string;
+    await fsPromises.writeFile(rootResolve('.lock'), ''); // this will lock the test run completion
+    const onGoingStrykerRun = execa('node', [path.resolve('..', '..', 'node_modules', '.bin', 'stryker'), 'run']);
+    onGoingStrykerRun.stdout.on('data', async (data) => {
+      if (data.toString().includes('Starting initial test run')) {
+        addJSMutatedContent = await readAddJS();
+
+        // Now, mr bond, it is time to die!
+        onGoingStrykerRun.kill();
+      }
+    });
+
+    // Act
+    await expect(onGoingStrykerRun).rejected;
+
+    // Assert
+    expect(await readAddJS()).eq(originalAddJSContent);
+    expect(addJSMutatedContent).not.eq(originalAddJSContent);
+  });
+});

e2e/test/karma-mocha/package.json

@@ -6,8 +6,12 @@
   "main": "index.js",
   "scripts": {
     "pretest": "rimraf \"reports\"",
-    "test": "stryker run stryker.conf.js",
-    "posttest": "mocha --require ../../tasks/ts-node-register.js verify/*.ts"
+    "test": "npm run test:not-in-place && npm run test:in-place",
+    "test:not-in-place": "stryker run stryker.conf.js",
+    "posttest:not-in-place": "npm run verify",
+    "test:in-place": "stryker run stryker.conf.js --inPlace",
+    "posttest:in-place": "npm run verify",
+    "verify": "mocha --require ../../tasks/ts-node-register.js verify/*.ts"
   },
   "author": "",
   "license": "ISC"

packages/api/schema/stryker-core.json

@@ -294,6 +294,11 @@
         "type": "string"
       }
     },
+    "inPlace": {
+      "type": "boolean",
+      "description": "Determines whether or not Stryker should mutate your files in place. Note: mutating your files in place is generally not needed for mutation testing, unless you have a dependency in your project that is really dependent on the file locations (like \"app-root-path\" for example).\n\nWhen `true`, Stryker will override your files, but it will keep a copy of the originals in the temp directory (using `tempDirName`) and it will place the originals back after it is done.\n\nWhen `false` (default) Stryker will work in the copy of your code inside the temp directory.",
+      "default": false
+    },
     "logLevel": {
       "description": "Set the log level that Stryker uses to write to the console.",
       "$ref": "#/definitions/logLevel",

packages/core/src/di/build-main-injector.ts

@@ -9,6 +9,7 @@ import ConfigReader from '../config/config-reader';
 import BroadcastReporter from '../reporters/broadcast-reporter';
 import { TemporaryDirectory } from '../utils/temporary-directory';
 import Timer from '../utils/timer';
+import { UnexpectedExitHandler } from '../unexpected-exit-handler';
 
 import { pluginResolverFactory } from './factory-methods';
 
@@ -21,11 +22,13 @@ export interface MainContext extends PluginContext {
   [coreTokens.timer]: I<Timer>;
   [coreTokens.temporaryDirectory]: I<TemporaryDirectory>;
   [coreTokens.execa]: typeof execa;
+  [coreTokens.process]: NodeJS.Process;
+  [coreTokens.unexpectedExitRegistry]: I<UnexpectedExitHandler>;
 }
 
 type PluginResolverProvider = Injector<PluginContext>;
-export type CliOptionsProvider = Injector<Pick<MainContext, 'logger' | 'getLogger'> & { [coreTokens.cliOptions]: PartialStrykerOptions }>;
 
+export type CliOptionsProvider = Injector<Pick<MainContext, 'logger' | 'getLogger'> & { [coreTokens.cliOptions]: PartialStrykerOptions }>;
 buildMainInjector.inject = tokens(commonTokens.injector);
 export function buildMainInjector(injector: CliOptionsProvider): Injector<MainContext> {
   const pluginResolverProvider = createPluginResolverProvider(injector);
@@ -35,7 +38,9 @@ export function buildMainInjector(injector: CliOptionsProvider): Injector<MainCo
     .provideClass(coreTokens.reporter, BroadcastReporter)
     .provideClass(coreTokens.temporaryDirectory, TemporaryDirectory)
     .provideClass(coreTokens.timer, Timer)
-    .provideValue(coreTokens.execa, execa);
+    .provideValue(coreTokens.execa, execa)
+    .provideValue(coreTokens.process, process)
+    .provideClass(coreTokens.unexpectedExitRegistry, UnexpectedExitHandler);
 }
 
 export function createPluginResolverProvider(parent: CliOptionsProvider): PluginResolverProvider {

packages/core/src/di/core-tokens.ts

@@ -5,21 +5,19 @@ export const disableTypeChecksHelper = 'disableTypeChecksHelper';
 export const execa = 'execa';
 export const cliOptions = 'cliOptions';
 export const configReader = 'configReader';
-export const configOptionsApplier = 'configOptionsApplier'; // TODO: Remove if unused post mutation switching
 export const inputFiles = 'inputFiles';
 export const dryRunResult = 'dryRunResult';
-export const transpiledFiles = 'transpiledFiles'; // TODO: Remove if unused post mutation switching
 export const files = 'files';
 export const mutants = 'mutants';
 export const mutantsWithTestCoverage = 'mutantsWithTestCoverage';
-export const mutantTranspileScheduler = 'mutantTranspileScheduler'; // TODO: Remove if unused post mutation switching
+export const process = 'process';
 export const temporaryDirectory = 'temporaryDirectory';
+export const unexpectedExitRegistry = 'unexpectedExitRegistry';
 export const timer = 'timer';
 export const timeOverheadMS = 'timeOverheadMS';
 export const loggingContext = 'loggingContext';
 export const mutationTestReportHelper = 'mutationTestReportHelper';
 export const sandbox = 'sandbox';
-export const sandboxWorkingDirectory = 'sandboxWorkingDirectory'; // TODO: Remove if unused post mutation switching
 export const concurrencyTokenProvider = 'concurrencyTokenProvider';
 export const testRunnerFactory = 'testRunnerFactory';
 export const testRunnerPool = 'testRunnerPool';