feat(init): add buildCommand question when running (#3213)

On running `stryker init`, the user is prompted for a custom build command to run provided that they do not choose the jest test runner.

![image](https://user-images.githubusercontent.com/44368997/137911833-801d7637-eca3-450c-a7d6-d03078581dc6.png)

Co-authored-by: Nico Jansen <jansennico@gmail.com>

packages/core/src/initializer/stryker-config-writer.ts

@@ -38,6 +38,7 @@ export class StrykerConfigWriter {
    */
   public write(
     selectedTestRunner: PromptOption,
+    buildCommand: PromptOption,
     selectedReporters: PromptOption[],
     selectedPackageManager: PromptOption,
     additionalPiecesOfConfig: Array<Partial<StrykerOptions>>,
@@ -50,6 +51,9 @@ export class StrykerConfigWriter {
       coverageAnalysis: CommandTestRunner.is(selectedTestRunner.name) ? 'off' : 'perTest',
     };
 
+    // Only write buildCommand to config file if non-empty
+    if (buildCommand.name) configObject.buildCommand = buildCommand.name;
+
     Object.assign(configObject, ...additionalPiecesOfConfig);
     return this.writeStrykerConfig(configObject, exportAsJson);
   }

packages/core/src/initializer/stryker-initializer.ts

@@ -98,12 +98,14 @@ export class StrykerInitializer {
 
   private async initiateCustom(configWriter: StrykerConfigWriter) {
     const selectedTestRunner = await this.selectTestRunner();
+    const buildCommand = await this.getBuildCommand(selectedTestRunner);
     const selectedReporters = await this.selectReporters();
     const selectedPackageManager = await this.selectPackageManager();
     const isJsonSelected = await this.selectJsonConfigType();
     const npmDependencies = this.getSelectedNpmDependencies([selectedTestRunner].concat(selectedReporters));
     const configFileName = await configWriter.write(
       selectedTestRunner,
+      buildCommand,
       selectedReporters,
       selectedPackageManager,
       await this.fetchAdditionalConfig(npmDependencies),
@@ -122,6 +124,11 @@ export class StrykerInitializer {
     return this.inquirer.promptTestRunners(testRunnerOptions);
   }
 
+  private async getBuildCommand(selectedTestRunner: PromptOption): Promise<PromptOption> {
+    const shouldSkipQuestion = selectedTestRunner.name === 'jest';
+    return this.inquirer.promptBuildCommand(shouldSkipQuestion);
+  }
+
   private async selectReporters(): Promise<PromptOption[]> {
     const reporterOptions = await this.client.getTestReporterOptions();
     reporterOptions.push(

packages/core/src/initializer/stryker-inquirer.ts

@@ -43,6 +43,18 @@ export class StrykerInquirer {
     }
   }
 
+  public async promptBuildCommand(skip: boolean): Promise<PromptOption> {
+    const { buildCommand } = await inquirer.prompt<{ buildCommand: string }>({
+      message:
+        'What build command should be executed just before running your tests? For example: "npm run build" or "tsc -b" (leave empty when this is not needed).',
+      name: 'buildCommand',
+      default: 'none',
+      when: !skip,
+    });
+
+    return { name: buildCommand !== 'none' ? buildCommand : '', pkg: null };
+  }
+
   public async promptReporters(options: PromptOption[]): Promise<PromptOption[]> {
     const answers = await inquirer.prompt<{ reporters: string[] }>({
       choices: options.map((_) => _.name),

packages/core/test/unit/initializer/stryker-initializer.spec.ts

@@ -62,7 +62,7 @@ describe(StrykerInitializer.name, () => {
 
   describe('initialize()', () => {
     beforeEach(() => {
-      stubTestRunners('@stryker-mutator/awesome-runner', 'stryker-hyper-runner', 'stryker-ghost-runner');
+      stubTestRunners('@stryker-mutator/awesome-runner', 'stryker-hyper-runner', 'stryker-ghost-runner', '@stryker-mutator/jest-runner');
       stubMutators('@stryker-mutator/typescript', '@stryker-mutator/javascript-mutator');
       stubReporters('stryker-dimension-reporter', '@stryker-mutator/mars-reporter');
       stubPackageClient({
@@ -77,6 +77,7 @@ describe(StrykerInitializer.name, () => {
           files: [],
           someOtherSetting: 'enabled',
         },
+        '@stryker-mutator/jest-runner': null,
       });
       fsWriteFile.resolves();
       presets.push(presetMock);
@@ -91,20 +92,24 @@ describe(StrykerInitializer.name, () => {
 
       await sut.initialize();
 
-      expect(inquirerPrompt).callCount(5);
-      const [promptPreset, promptTestRunner, promptReporters, promptPackageManagers, promptConfigTypes]: inquirer.ListQuestion[] = [
-        inquirerPrompt.getCall(0).args[0],
-        inquirerPrompt.getCall(1).args[0],
-        inquirerPrompt.getCall(2).args[0],
-        inquirerPrompt.getCall(3).args[0],
-        inquirerPrompt.getCall(4).args[0],
-      ];
+      expect(inquirerPrompt).callCount(6);
+      const [promptPreset, promptTestRunner, promptBuildCommand, promptReporters, promptPackageManagers, promptConfigTypes]: inquirer.ListQuestion[] =
+        [
+          inquirerPrompt.getCall(0).args[0],
+          inquirerPrompt.getCall(1).args[0],
+          inquirerPrompt.getCall(2).args[0],
+          inquirerPrompt.getCall(3).args[0],
+          inquirerPrompt.getCall(4).args[0],
+          inquirerPrompt.getCall(5).args[0],
+        ];
+
       expect(promptPreset.type).to.eq('list');
       expect(promptPreset.name).to.eq('preset');
       expect(promptPreset.choices).to.deep.eq(['awesome-preset', new inquirer.Separator(), 'None/other']);
       expect(promptTestRunner.type).to.eq('list');
       expect(promptTestRunner.name).to.eq('testRunner');
-      expect(promptTestRunner.choices).to.deep.eq(['awesome', 'hyper', 'ghost', new inquirer.Separator(), 'command']);
+      expect(promptTestRunner.choices).to.deep.eq(['awesome', 'hyper', 'ghost', 'jest', new inquirer.Separator(), 'command']);
+      expect(promptBuildCommand.name).to.eq('buildCommand');
       expect(promptReporters.type).to.eq('checkbox');
       expect(promptReporters.choices).to.deep.eq(['dimension', 'mars', 'html', 'clear-text', 'progress', 'dashboard']);
       expect(promptPackageManagers.type).to.eq('list');
@@ -249,6 +254,53 @@ describe(StrykerInitializer.name, () => {
       expect(fs.promises.writeFile).calledWith('stryker.conf.json', sinon.match('"files": []'));
     });
 
+    it('should not prompt for buildCommand if test runner is jest', async () => {
+      inquirerPrompt.resolves({
+        packageManager: 'npm',
+        reporters: ['dimension', 'mars', 'progress'],
+        testRunner: 'jest',
+        configType: 'JSON',
+        buildCommand: 'none',
+      });
+
+      await sut.initialize();
+
+      const promptBuildCommand = inquirerPrompt.getCalls().filter((call) => call.args[0].name === 'buildCommand');
+      expect(promptBuildCommand.length === 1);
+      expect(promptBuildCommand[0].args[0].when).to.be.false;
+      expect(fs.promises.writeFile).calledWith(
+        'stryker.conf.json',
+        sinon.match((val) => !val.includes('"buildCommand": '))
+      );
+    });
+
+    it('should not write "buildCommand" config option if empty buildCommand entered', async () => {
+      inquirerPrompt.resolves({
+        packageManager: 'npm',
+        reporters: [],
+        testRunner: 'hyper',
+        configType: 'JSON',
+        buildCommand: 'none',
+      });
+      await sut.initialize();
+      expect(fs.promises.writeFile).calledWith(
+        'stryker.conf.json',
+        sinon.match((val) => !val.includes('"buildCommand": '))
+      );
+    });
+
+    it('should save entered build command', async () => {
+      inquirerPrompt.resolves({
+        packageManager: 'npm',
+        reporters: [],
+        testRunner: 'hyper',
+        configType: 'JSON',
+        buildCommand: 'npm run build',
+      });
+      await sut.initialize();
+      expect(fs.promises.writeFile).calledWith('stryker.conf.json', sinon.match('"buildCommand": "npm run build"'));
+    });
+
     it('should set "coverageAnalysis" to "off" when the command test runner is chosen', async () => {
       inquirerPrompt.resolves({
         packageManager: 'npm',