fix(JestTestRunner): run jest with --findRelatedTests

packages/stryker-api/src/test_runner/RunOptions.ts

@@ -12,6 +12,8 @@ interface RunOptions {
    * It should be loaded right after the test framework but right before any tests can run.
    */
   testHooks?: string;
+
+  mutatedFileName?: string;
 }
 
 export default RunOptions;

packages/stryker-jest-runner/src/JestTestRunner.ts

@@ -1,12 +1,13 @@
 import { getLogger } from 'stryker-api/logging';
-import { RunnerOptions, RunResult, TestRunner, RunStatus, TestResult, TestStatus } from 'stryker-api/test_runner';
+import { RunnerOptions, RunResult, TestRunner, RunStatus, TestResult, TestStatus, RunOptions } from 'stryker-api/test_runner';
 import * as jest from 'jest';
 import JestTestAdapterFactory from './jestTestAdapters/JestTestAdapterFactory';
 
 export default class JestTestRunner implements TestRunner {
   private readonly log = getLogger(JestTestRunner.name);
   private readonly jestConfig: jest.Configuration;
   private readonly processEnvRef: NodeJS.ProcessEnv;
+  private readonly enableFindRelatedTests: boolean;
 
   public constructor(options: RunnerOptions, processEnvRef?: NodeJS.ProcessEnv) {
     // Make sure process can be mocked by tests by passing it in the constructor
@@ -15,19 +16,25 @@ export default class JestTestRunner implements TestRunner {
     // Get jest configuration from stryker options and assign it to jestConfig
     this.jestConfig = options.strykerOptions.jest.config;
 
+    // Get enableFindRelatedTests from stryker jest options or default to true
+    this.enableFindRelatedTests = options.strykerOptions.jest.enableFindRelatedTests;
+    if (this.enableFindRelatedTests === undefined) {
+      this.enableFindRelatedTests = true;
+    }
+
     // basePath will be used in future releases of Stryker as a way to define the project root
     // Default to process.cwd when basePath is not set for now, should be removed when issue is solved
     // https://github.com/stryker-mutator/stryker/issues/650
     this.jestConfig.rootDir = options.strykerOptions.basePath || process.cwd();
     this.log.debug(`Project root is ${this.jestConfig.rootDir}`);
   }
 
-  public async run(): Promise<RunResult> {
+  public async run(options?: RunOptions): Promise<RunResult> {
     this.setNodeEnv();
 
     const jestTestRunner = JestTestAdapterFactory.getJestTestAdapter();
 
-    const { results } = await jestTestRunner.run(this.jestConfig, process.cwd());
+    const { results } = await jestTestRunner.run(this.jestConfig, process.cwd(), this.enableFindRelatedTests, options && options.mutatedFileName);
 
     // Get the non-empty errorMessages from the jest RunResult, it's safe to cast to Array<string> here because we filter the empty error messages
     const errorMessages = results.testResults.map((testSuite: jest.TestResult) => testSuite.failureMessage).filter(errorMessage => (errorMessage)) as string[];

packages/stryker-jest-runner/src/jestTestAdapters/JestPromiseTestAdapter.ts

@@ -5,12 +5,16 @@ import { Configuration, runCLI, RunResult } from 'jest';
 export default class JestPromiseTestAdapter implements JestTestAdapter {
   private readonly log = getLogger(JestPromiseTestAdapter.name);
 
-  public run(jestConfig: Configuration, projectRoot: string): Promise<RunResult> {
+  public run(jestConfig: Configuration, projectRoot: string, enableFindRelatedTests: boolean, mutatedFileName?: string): Promise<RunResult> {
     jestConfig.reporters = [];
     const config = JSON.stringify(jestConfig);
     this.log.trace(`Invoking Jest with config ${config}`);
+    if (enableFindRelatedTests && mutatedFileName) {
+      this.log.trace(`Only running tests related to ${mutatedFileName}`);
+    }
 
     return runCLI({
+      ...(enableFindRelatedTests && mutatedFileName && { _: [mutatedFileName], findRelatedTests: true}),
       config,
       runInBand: true,
       silent: true

packages/stryker-jest-runner/src/jestTestAdapters/JestTestAdapter.ts

@@ -1,5 +1,5 @@
 import { RunResult } from 'jest';
 
 export default interface JestTestAdapter {
-  run(config: object, projectRoot: string): Promise<RunResult>;
+  run(config: object, projectRoot: string, enableFindRelatedTests: boolean, mutatedFileName?: string): Promise<RunResult>;
 }

packages/stryker-jest-runner/test/unit/jestTestAdapters/JestPromiseTestAdapterSpec.ts

@@ -22,13 +22,13 @@ describe('JestPromiseTestAdapter', () => {
   });
 
   it('should set reporters to an empty array', async () => {
-    await jestPromiseTestAdapter.run(jestConfig, projectRoot);
+    await jestPromiseTestAdapter.run(jestConfig, projectRoot, true);
 
     expect(jestConfig.reporters).to.be.an('array').that.is.empty;
   });
 
   it('should call the runCLI method with the correct projectRoot', async () => {
-    await jestPromiseTestAdapter.run(jestConfig, projectRoot);
+    await jestPromiseTestAdapter.run(jestConfig, projectRoot, true);
 
     assert(runCLIStub.calledWith({
       config: JSON.stringify({ rootDir: projectRoot, reporters: [] }),
@@ -38,7 +38,7 @@ describe('JestPromiseTestAdapter', () => {
   });
 
   it('should call the runCLI method and return the test result', async () => {
-    const result = await jestPromiseTestAdapter.run(jestConfig, projectRoot);
+    const result = await jestPromiseTestAdapter.run(jestConfig, projectRoot, true);
 
     expect(result).to.deep.equal({
       config: {
@@ -51,7 +51,7 @@ describe('JestPromiseTestAdapter', () => {
   });
 
   it('should trace log a message when jest is invoked', async () => {
-    await jestPromiseTestAdapter.run(jestConfig, projectRoot);
+    await jestPromiseTestAdapter.run(jestConfig, projectRoot, true);
 
     const expectedResult: any = JSON.parse(JSON.stringify(jestConfig));
     expectedResult.reporters = [];

packages/stryker-jest-runner/types/jest/index.d.ts

@@ -8,6 +8,8 @@ declare namespace Jest {
     config: string;
     runInBand: boolean;
     silent: boolean;
+    findRelatedTests?: boolean;
+    _?: string[];
   }
 
   // Taken from https://goo.gl/qHifyP, removed all stuff that we are not using
@@ -18,7 +20,7 @@ declare namespace Jest {
     collectCoverage: boolean;
     verbose: boolean;
     testResultsProcessor: Maybe<string>;
-    testEnvironment: string
+    testEnvironment: string;
   }
 
   interface RunResult {

packages/stryker/src/Sandbox.ts

@@ -44,8 +44,8 @@ export default class Sandbox {
     return sandbox.initialize().then(() => sandbox);
   }
 
-  public run(timeout: number, testHooks: string | undefined): Promise<RunResult> {
-    return this.testRunner.run({ timeout, testHooks });
+  public run(timeout: number, testHooks: string | undefined, mutant?: TestableMutant): Promise<RunResult> {
+    return this.testRunner.run({ timeout, testHooks, ...(mutant && { mutatedFileName: this.fileMap[mutant.fileName]}) });
   }
 
   public dispose(): Promise<void> {
@@ -58,7 +58,7 @@ export default class Sandbox {
       this.log.warn(`Failed find coverage data for this mutant, running all tests. This might have an impact on performance: ${transpiledMutant.mutant.toString()}`);
     }
     await Promise.all(mutantFiles.map(mutatedFile => this.writeFileInSandbox(mutatedFile)));
-    const runResult = await this.run(this.calculateTimeout(transpiledMutant.mutant), this.getFilterTestsHooks(transpiledMutant.mutant));
+    const runResult = await this.run(this.calculateTimeout(transpiledMutant.mutant), this.getFilterTestsHooks(transpiledMutant.mutant), transpiledMutant.mutant);
     await this.reset(mutantFiles);
     return runResult;
   }

packages/stryker/test/unit/SandboxSpec.ts

@@ -196,13 +196,17 @@ describe('Sandbox', () => {
       expect(testFrameworkStub.filter).to.have.been.calledWith(transpiledMutant.mutant.selectedTests);
     });
 
-    it('should provide the filter code as testHooks and correct timeout', async () => {
+    it('should provide the filter code as testHooks, correct timeout and mutatedFileName', async () => {
       options.timeoutMS = 1000;
       const overheadTimeMS = 42;
       const totalTimeSpend = 12;
       const sut = await Sandbox.create(options, SANDBOX_INDEX, files, testFrameworkStub, overheadTimeMS, LOGGING_CONTEXT);
       await sut.runMutant(transpiledMutant);
-      const expectedRunOptions = { testHooks: wrapInClosure(testFilterCodeFragment), timeout: totalTimeSpend * options.timeoutFactor + options.timeoutMS + overheadTimeMS };
+      const expectedRunOptions = {
+        mutatedFileName: path.resolve('random-folder-3', 'file1'),
+        testHooks: wrapInClosure(testFilterCodeFragment),
+        timeout: totalTimeSpend * options.timeoutFactor + options.timeoutMS + overheadTimeMS
+      };
       expect(testRunner.run).calledWith(expectedRunOptions);
     });