diff --git a/packages/cli/src/cmds/preview/task.ts b/packages/cli/src/cmds/preview/task.ts
index 2042e8d8b36..4cf9393ba33 100644
--- a/packages/cli/src/cmds/preview/task.ts
+++ b/packages/cli/src/cmds/preview/task.ts
@@ -3,7 +3,7 @@
 
 "use strict";
 
-import { ChildProcess, spawn } from "child_process";
+import cp from "child_process";
 import { err, FxError, LogLevel, ok, Result } from "@microsoft/teamsfx-api";
 import treeKill from "tree-kill";
 import { ServiceLogWriter } from "./serviceLogWriter";
@@ -33,7 +33,7 @@ export class Task {
   private options?: TaskOptions;
 
   private resolved = false;
-  private task: ChildProcess | undefined;
+  private task: cp.ChildProcess | undefined;
 
   constructor(
     taskTitle: string,
@@ -61,26 +61,25 @@ export class Task {
     ) => Promise<FxError | null>
   ): Promise<Result<TaskResult, FxError>> {
     await startCallback(this.taskTitle, this.background);
-    this.task = spawn(this.command, this.args, this.options);
+    this.task = cp.spawn(this.command, this.args, this.options);
     const stdout: string[] = [];
     const stderr: string[] = [];
     return new Promise((resolve) => {
       this.task?.stdout?.on("data", (data) => {
-        // TODO: log
         stdout.push(data.toString());
       });
       this.task?.stderr?.on("data", (data) => {
-        // TODO: log
         stderr.push(data.toString());
       });
-      this.task?.on("exit", async () => {
+      // eslint-disable-next-line @typescript-eslint/no-misused-promises
+      this.task?.on("exit", async (code) => {
         const result: TaskResult = {
           command: this.command,
           options: this.options,
-          success: this.task?.exitCode === 0,
+          success: code === 0,
           stdout: stdout,
           stderr: stderr,
-          exitCode: this.task?.exitCode === undefined ? null : this.task?.exitCode,
+          exitCode: code,
         };
         const error = await stopCallback(this.taskTitle, this.background, result);
         if (error) {
@@ -93,7 +92,7 @@ export class Task {
   }
 
   /**
-   * wait until stdout of the task matches the pattern or the task ends
+   * wait until stdout/stderr of the task matches the pattern or the task ends
    */
   public async waitFor(
     pattern: RegExp,
@@ -116,18 +115,19 @@ export class Task {
       `${this.command} ${this.args ? this.args?.join(" ") : ""}\n`
     );
     await startCallback(this.taskTitle, this.background, serviceLogWriter);
-    this.task = spawn(this.command, this.args, this.options);
+    this.task = cp.spawn(this.command, this.args, this.options);
     const stdout: string[] = [];
     const stderr: string[] = [];
     return new Promise((resolve) => {
       if (timeout !== undefined) {
+        // eslint-disable-next-line @typescript-eslint/no-misused-promises
         setTimeout(async () => {
           if (!this.resolved) {
             this.resolved = true;
             const result: TaskResult = {
               command: this.command,
               options: this.options,
-              success: true,
+              success: false,
               stdout: stdout,
               stderr: stderr,
               exitCode: null,
@@ -142,6 +142,7 @@ export class Task {
         }, timeout);
       }
 
+      // eslint-disable-next-line @typescript-eslint/no-misused-promises
       this.task?.stdout?.on("data", async (data) => {
         const dataStr = data.toString();
         await serviceLogWriter?.write(this.taskTitle, dataStr);
@@ -170,6 +171,7 @@ export class Task {
           }
         }
       });
+      // eslint-disable-next-line @typescript-eslint/no-misused-promises
       this.task?.stderr?.on("data", async (data) => {
         const dataStr = data.toString();
         await serviceLogWriter?.write(this.taskTitle, dataStr);
@@ -177,9 +179,30 @@ export class Task {
           logProvider.necessaryLog(LogLevel.Info, dataStr.trim(), true);
         }
         stderr.push(dataStr);
+        if (!this.resolved) {
+          const match = pattern.test(dataStr);
+          if (match) {
+            this.resolved = true;
+            const result: TaskResult = {
+              command: this.command,
+              options: this.options,
+              success: false,
+              stdout: stdout,
+              stderr: stderr,
+              exitCode: null,
+            };
+            const error = await stopCallback(this.taskTitle, this.background, result);
+            if (error) {
+              resolve(err(error));
+            } else {
+              resolve(ok(result));
+            }
+          }
+        }
       });
 
-      this.task?.on("exit", async () => {
+      // eslint-disable-next-line @typescript-eslint/no-misused-promises
+      this.task?.on("exit", async (code) => {
         if (!this.resolved) {
           this.resolved = true;
           const result: TaskResult = {
@@ -188,7 +211,7 @@ export class Task {
             success: false,
             stdout: stdout,
             stderr: stderr,
-            exitCode: this.task?.exitCode === undefined ? null : this.task?.exitCode,
+            exitCode: code,
           };
           const error = await stopCallback(this.taskTitle, this.background, result);
           if (error) {
diff --git a/packages/cli/tests/unit/cmds/preview/task.tests.ts b/packages/cli/tests/unit/cmds/preview/task.tests.ts
new file mode 100644
index 00000000000..dcc50a6bce5
--- /dev/null
+++ b/packages/cli/tests/unit/cmds/preview/task.tests.ts
@@ -0,0 +1,158 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+import * as sinon from "sinon";
+import { EventEmitter } from "events";
+import cp from "child_process";
+import { Readable } from "stream";
+import { Task } from "../../../../src/cmds/preview/task";
+import { expect } from "../../utils";
+
+function delay(ms: number) {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}
+
+describe("Task", () => {
+  describe("wait", () => {
+    let sandbox: sinon.SinonSandbox;
+
+    afterEach(() => {
+      sandbox.restore();
+    });
+
+    it("happy path", async () => {
+      sandbox = sinon.createSandbox();
+      const startCallback = sinon.stub().resolves();
+      const stopCallback = sinon.stub().resolves(null);
+      const spawnEvent = <cp.ChildProcess>new EventEmitter();
+      spawnEvent.stdout = <Readable>new EventEmitter();
+      spawnEvent.stderr = <Readable>new EventEmitter();
+      sandbox.stub(cp, "spawn").callsFake(() => {
+        return spawnEvent;
+      });
+
+      const task = new Task("taskTitle", false, "command");
+      const promise = task.wait(startCallback, stopCallback);
+
+      await delay(10);
+
+      spawnEvent.stdout.emit("data", "stdout1");
+      spawnEvent.stdout.emit("data", "stdout2");
+      spawnEvent.stderr.emit("data", "stderr1");
+      spawnEvent.stderr.emit("data", "stderr2");
+      spawnEvent.emit("exit", 0);
+
+      const resultRes = await promise;
+
+      expect(resultRes.isOk()).to.be.true;
+      const result = (resultRes as any).value;
+      expect(result.success).to.be.true;
+      expect(result.stdout).to.deep.equals(["stdout1", "stdout2"]);
+      expect(result.stderr).to.deep.equals(["stderr1", "stderr2"]);
+      expect(result.exitCode).to.equals(0);
+    });
+  });
+
+  describe("waitFor", () => {
+    let sandbox: sinon.SinonSandbox;
+
+    afterEach(() => {
+      sandbox.restore();
+    });
+
+    it("happy path: match stdout", async () => {
+      sandbox = sinon.createSandbox();
+      const startCallback = sinon.stub().resolves();
+      const stopCallback = sinon.stub().resolves(null);
+      const spawnEvent = <cp.ChildProcess>new EventEmitter();
+      spawnEvent.stdout = <Readable>new EventEmitter();
+      spawnEvent.stderr = <Readable>new EventEmitter();
+      sandbox.stub(cp, "spawn").callsFake(() => {
+        return spawnEvent;
+      });
+
+      const task = new Task("taskTitle", true, "command");
+      const promise = task.waitFor(new RegExp("started", "i"), startCallback, stopCallback);
+
+      await delay(5);
+
+      spawnEvent.stdout.emit("data", "stdout1");
+      spawnEvent.stdout.emit("data", "stdout2");
+      spawnEvent.stdout.emit("data", "xxx started xxx");
+      spawnEvent.stderr.emit("data", "stderr1");
+      spawnEvent.stderr.emit("data", "stderr2");
+
+      const resultRes = await promise;
+
+      expect(resultRes.isOk()).to.be.true;
+      const result = (resultRes as any).value;
+      expect(result.success).to.be.true;
+      expect(result.stdout).to.deep.equals(["stdout1", "stdout2", "xxx started xxx"]);
+      expect(result.stderr).to.deep.equals(["stderr1", "stderr2"]);
+      expect(result.exitCode).to.equals(null);
+    });
+
+    it("happy path: match stderr", async () => {
+      sandbox = sinon.createSandbox();
+      const startCallback = sinon.stub().resolves();
+      const stopCallback = sinon.stub().resolves(null);
+      const spawnEvent = <cp.ChildProcess>new EventEmitter();
+      spawnEvent.stdout = <Readable>new EventEmitter();
+      spawnEvent.stderr = <Readable>new EventEmitter();
+      sandbox.stub(cp, "spawn").callsFake(() => {
+        return spawnEvent;
+      });
+
+      const task = new Task("taskTitle", true, "command");
+      const promise = task.waitFor(new RegExp("started", "i"), startCallback, stopCallback);
+
+      await delay(5);
+
+      spawnEvent.stdout.emit("data", "stdout1");
+      spawnEvent.stdout.emit("data", "stdout2");
+      spawnEvent.stderr.emit("data", "stderr1");
+      spawnEvent.stderr.emit("data", "stderr2");
+      spawnEvent.stderr.emit("data", "xxx started xxx");
+
+      const resultRes = await promise;
+
+      expect(resultRes.isOk()).to.be.true;
+      const result = (resultRes as any).value;
+      expect(result.success).to.be.false;
+      expect(result.stdout).to.deep.equals(["stdout1", "stdout2"]);
+      expect(result.stderr).to.deep.equals(["stderr1", "stderr2", "xxx started xxx"]);
+      expect(result.exitCode).to.equals(null);
+    });
+
+    it("timeout", async () => {
+      sandbox = sinon.createSandbox();
+      const startCallback = sinon.stub().resolves();
+      const stopCallback = sinon.stub().resolves(null);
+      const spawnEvent = <cp.ChildProcess>new EventEmitter();
+      spawnEvent.stdout = <Readable>new EventEmitter();
+      spawnEvent.stderr = <Readable>new EventEmitter();
+      sandbox.stub(cp, "spawn").callsFake(() => {
+        return spawnEvent;
+      });
+
+      const task = new Task("taskTitle", true, "command");
+      const promise = task.waitFor(new RegExp("started", "i"), startCallback, stopCallback, 30);
+
+      await delay(5);
+
+      spawnEvent.stdout.emit("data", "stdout1");
+      spawnEvent.stdout.emit("data", "stdout2");
+      spawnEvent.stderr.emit("data", "stderr1");
+      spawnEvent.stderr.emit("data", "stderr2");
+
+      const resultRes = await promise;
+
+      expect(resultRes.isOk()).to.be.true;
+      const result = (resultRes as any).value;
+      expect(result.success).to.be.false;
+      expect(result.stdout).to.deep.equals(["stdout1", "stdout2"]);
+      expect(result.stderr).to.deep.equals(["stderr1", "stderr2"]);
+      expect(result.exitCode).to.equals(null);
+    });
+  });
+});