add useDashedArgs workspace setting

src/Runner.js

@@ -61,7 +61,7 @@ export default class Runner extends EventEmitter {
     // Handle the arg change on v18
     const belowEighteen = this.workspace.localJestMajorVersion < 18;
     const outputArg = belowEighteen ? '--jsonOutputFile' : '--outputFile';
-    const args = ['--testLocationInResults', '--json', '--useStderr', outputArg, this.outputPath];
+    let args = ['--testLocationInResults', '--json', '--useStderr', outputArg, this.outputPath];
     if (this.watchMode) {
       args.push(this.watchAll ? '--watchAll' : '--watch');
     }
@@ -88,6 +88,12 @@ export default class Runner extends EventEmitter {
     if (this.options.args) {
       args.push(...this.options.args.args);
     }
+    if (this.workspace.useDashedArgs) {
+      args = args.map((arg) =>
+        arg && arg.startsWith('--') && arg.length > 2 ? arg.replace(/(\B)([A-Z])/gm, '-$2').toLowerCase() : arg
+      );
+    }
+
     return args;
   }
 

src/__tests__/runner.test.js

@@ -302,6 +302,57 @@ describe('Runner', () => {
       const lastIndex = args.lastIndexOf('--reporters');
       expect(args[lastIndex + 1]).toBe(expected[1]);
     });
+
+    it('calls createProcess with camel cased args by default', () => {
+      const expected = '--testLocationInResults';
+
+      const workspace: any = {};
+      const options = {};
+      const sut = new Runner(workspace, options);
+      sut.start(false);
+
+      const args = (createProcess: any).mock.calls[0][1];
+      expect(args[0]).toBe(expected);
+    });
+
+    it('calls createProcess with dashed args when provided', () => {
+      const expected = '--test-location-in-results';
+
+      const workspace: any = {useDashedArgs: true};
+      const options = {};
+      const sut = new Runner(workspace, options);
+      sut.start(false);
+
+      const args = (createProcess: any).mock.calls[0][1];
+      expect(args[0]).toBe(expected);
+    });
+
+    it('converts user passed in args', () => {
+      const expected = '--foo-bar-baz';
+
+      const workspace: any = {useDashedArgs: true};
+      const options = {args: {args: ['--fooBarBaz']}};
+      const sut = new Runner(workspace, options);
+      sut.start(false);
+
+      const args = (createProcess: any).mock.calls[0][1];
+      const index = args.indexOf(expected);
+      expect(index).not.toBe(-1);
+    });
+
+    it('does not alter already dashed args when provided', () => {
+      const expected = '--foo-bar-baz';
+
+      const workspace: any = {useDashedArgs: true};
+      const options = {args: {args: [expected]}};
+      const sut = new Runner(workspace, options);
+      sut.start(false);
+
+      const args = (createProcess: any).mock.calls[0][1];
+      const index = args.indexOf(expected);
+      expect(index).not.toBe(-1);
+    });
+
     describe('RunArgs', () => {
       it.each`
         runArgs                                   | containedArgs

src/project_workspace.ts

@@ -26,6 +26,7 @@ export interface ProjectWorkspaceConfig {
   debug?: boolean;
   nodeEnv?: {[key: string]: string | undefined};
   shell?: string | LoginShell;
+  useDashedArgs?: boolean;
 }
 
 /**
@@ -121,6 +122,11 @@ export default class ProjectWorkspace {
    */
   shell?: string | LoginShell;
 
+  /**
+   * Wether dashed args should be used for the jest command line. Default is false.
+   */
+  useDashedArgs?: boolean;
+
   constructor(
     rootPath: string,
     jestCommandLine: string,
@@ -130,7 +136,8 @@ export default class ProjectWorkspace {
     collectCoverage?: boolean,
     debug?: boolean,
     nodeEnv?: {[key: string]: string | undefined},
-    shell?: string | LoginShell
+    shell?: string | LoginShell,
+    useDashedArgs?: boolean
   ) {
     this.rootPath = rootPath;
     this.jestCommandLine = jestCommandLine;
@@ -141,6 +148,7 @@ export default class ProjectWorkspace {
     this.debug = debug;
     this.nodeEnv = nodeEnv;
     this.shell = shell;
+    this.useDashedArgs = useDashedArgs;
   }
 }
 
@@ -160,6 +168,7 @@ export const createProjectWorkspace = (config: ProjectWorkspaceConfig): ProjectW
     config.collectCoverage,
     config.debug,
     config.nodeEnv,
-    config.shell
+    config.shell,
+    config.useDashedArgs
   );
 };