fix debug auto config for win32 jest command

src/DebugConfigurationProvider.ts

@@ -1,5 +1,6 @@
 import * as vscode from 'vscode';
 import * as path from 'path';
+import * as fs from 'fs';
 
 import {
   toFilePath,
@@ -8,6 +9,7 @@ import {
   escapeRegExp,
   parseCmdLine,
 } from './helpers';
+import { platform } from 'os';
 
 export const DEBUG_CONFIG_PLATFORMS = ['windows', 'linux', 'osx'];
 const testNamePatternRegex = /\$\{jest.testNamePattern\}/g;
@@ -204,11 +206,12 @@ export class DebugConfigurationProvider implements vscode.DebugConfigurationProv
       };
     } else {
       // convert the cmd to absolute path
-      const program = path.isAbsolute(cmd)
+      let program = path.isAbsolute(cmd)
         ? cmd
         : absoluteRootPath
         ? path.resolve(absoluteRootPath, cmd)
         : ['${workspaceFolder}', cmd].join(path.sep);
+      program = this.adjustProgram(program);
       const args = [...cmdArgs, ...config.args];
       finalConfig = { ...finalConfig, cwd, program, args };
     }
@@ -218,4 +221,19 @@ export class DebugConfigurationProvider implements vscode.DebugConfigurationProv
 
     return finalConfig;
   }
+
+  // adopt program/command for debug purpose
+  private adjustProgram(program: string): string {
+    if (platform() === 'win32' && program.endsWith('\\node_modules\\.bin\\jest.cmd')) {
+      const newProgram = program.replace(
+        '\\node_modules\\.bin\\jest.cmd',
+        '\\node_modules\\jest\\bin\\jest.js'
+      );
+      if (fs.existsSync(newProgram)) {
+        return newProgram;
+      }
+      throw new Error(`failed to find jest binary: ${newProgram}`);
+    }
+    return program;
+  }
 }

tests/DebugConfigurationProvider.test.ts

@@ -9,6 +9,7 @@ import {
   parseCmdLine,
 } from '../src/helpers';
 import * as os from 'os';
+import * as fs from 'fs';
 import { makeWorkspaceFolder } from './test-helper';
 
 describe('DebugConfigurationProvider', () => {
@@ -193,7 +194,7 @@ describe('DebugConfigurationProvider', () => {
           ${12} | ${false} | ${'"/dir with space/jest" --arg1=1 --arg2 2 "some string"'}   | ${{ cmd: '/dir with space/jest', args: ['--arg1=1', '--arg2', '2', '"some string"'], program: '/dir with space/jest' }}
           ${13} | ${false} | ${"'/dir with space/jest' --arg1=1 --arg2 2 'some string'"}   | ${{ cmd: '/dir with space/jest', args: ['--arg1=1', '--arg2', '2', "'some string'"], program: '/dir with space/jest' }}
           ${14} | ${false} | ${'jest --arg1 "escaped \\"this\\" string" --arg2 2'}         | ${{ cmd: 'jest', args: ['--arg1', '"escaped \\"this\\" string"', '--arg2', '2'], program: '${workspaceFolder}/jest' }}
-          ${15} | ${true}  | ${'.\\node_modules\\.bin\\jest'}                              | ${{ cmd: 'node_modules\\.bin\\jest', args: [], program: '${workspaceFolder}\\node_modules\\.bin\\jest' }}
+          ${15} | ${true}  | ${'.\\node_modules\\.bin\\jest.cmd'}                          | ${{ cmd: 'node_modules\\jest\\bin\\jest.js', args: [], program: '${workspaceFolder}\\node_modules\\jest\\bin\\jest.js' }}
           ${16} | ${true}  | ${'..\\jest --config="..\\jest-config.json"'}                 | ${{ cmd: '..\\jest', args: ['--config=', '"..\\jest-config.json"'], program: '${workspaceFolder}\\..\\jest' }}
           ${17} | ${true}  | ${'jest --config "..\\dir with space\\jest-config.json"'}     | ${{ cmd: 'jest', args: ['--config', '"..\\dir with space\\jest-config.json"'], program: '${workspaceFolder}\\jest' }}
           ${18} | ${true}  | ${'\\absolute\\jest --runInBand'}                             | ${{ cmd: '\\absolute\\jest', args: ['--runInBand'], program: '\\absolute\\jest' }}
@@ -204,6 +205,8 @@ describe('DebugConfigurationProvider', () => {
             if (!canRunTest(isWin32)) {
               return;
             }
+
+            (fs.existsSync as jest.Mocked<any>) = jest.fn().mockReturnValue(true);
             // eslint-disable-next-line @typescript-eslint/no-unused-vars
             const { args, program, windows, ...restConfig } = config;
             const sut = new DebugConfigurationProvider();
@@ -229,6 +232,32 @@ describe('DebugConfigurationProvider', () => {
         const sut = new DebugConfigurationProvider();
         expect(() => sut.withCommandLine(workspace, cmdLine)).toThrow('invalid cmdLine');
       });
+      describe('on win32, should throw error if the raw jest binary can not be found', () => {
+        let platformSpy;
+        beforeAll(() => {
+          platformSpy = jest.spyOn(os, 'platform').mockImplementation(() => 'win32');
+        });
+        afterAll(() => {
+          platformSpy.mockRestore();
+        });
+        it.each`
+          exists
+          ${true}
+          ${false}
+        `('file exists = $exists', ({ exists }) => {
+          (fs.existsSync as jest.Mocked<any>) = jest.fn().mockReturnValue(exists);
+          const sut = new DebugConfigurationProvider();
+          if (!exists) {
+            expect(() =>
+              sut.withCommandLine(workspace, 'whatever\\node_modules\\.bin\\jest.cmd')
+            ).toThrow();
+          } else {
+            expect(() =>
+              sut.withCommandLine(workspace, 'whatever\\node_modules\\.bin\\jest.cmd')
+            ).not.toThrow();
+          }
+        });
+      });
       it.each`
         cmd       | cArgs                                           | appendExtraArg
         ${'yarn'} | ${['test']}                                     | ${false}