test: cover execArgv in watch mode

Author: Han5991

test/sequential/test-watch-mode-watch-flags.mjs

@@ -94,4 +94,31 @@ describe('watch mode - watch flags', { concurrency: !process.env.TEST_PARALLEL,
       `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
     ]);
   });
+
+  it('exposes watch flags through process.execArgv inside the watched script', async () => {
+    const projectDir = tmpdir.resolve('project-watch-exec-argv');
+    mkdirSync(projectDir);
+
+    const file = createTmpFile(`
+      console.log(JSON.stringify(process.execArgv));
+    `, '.js', projectDir);
+    const watchPath = path.join(projectDir, 'template.html');
+    writeFileSync(watchPath, '');
+
+    async function assertExecArgv(args, expected) {
+      const { stdout, stderr } = await runNode({
+        args, options: { cwd: projectDir }
+      });
+
+      assert.strictEqual(stderr, '');
+
+      const execArgvLine = stdout[0];
+      assert.deepStrictEqual(JSON.parse(execArgvLine), expected);
+      assert.match(stdout.at(-1), /^Completed running/);
+    }
+
+    await assertExecArgv(['--watch', file], ['--watch']);
+    await assertExecArgv(['--watch-path=template.html', file], ['--watch-path=template.html']);
+    await assertExecArgv(['--watch-path', 'template.html', file], ['--watch-path', 'template.html']);
+  });
 });