Tillitsdone
down Scroll to discover

Write Unit Tests with GoMock for Coverage

Learn how to effectively use GoMock for writing comprehensive unit tests in Go.

Master mocking techniques, improve code coverage, and create more reliable test suites for your Go applications.
thumbnail

How to Write Unit Tests with GoMock for Better Code Coverage

Aerial view of intertwining pathways forming abstract geometric patterns captured from directly above at 90-degree angle colors of amber and stone blue creating contrast between paths surrounded by natural earth tones high-quality ultra-realistic cinematic 8K UHD high resolution sharp and detail

Testing is a crucial aspect of software development that helps ensure our code works as intended. When it comes to Go programming, GoMock is a powerful mocking framework that enables us to write comprehensive unit tests. In this guide, we’ll explore how to leverage GoMock to improve your code coverage and create more reliable tests.

Understanding GoMock

GoMock is a mocking framework that lets you replace real implementations with mock objects during testing. This is particularly useful when testing code that depends on external services, databases, or complex interfaces. By using mocks, we can isolate the code we’re testing and ensure our tests are fast, reliable, and deterministic.

Abstract flowing patterns resembling code architecture viewed from a 45-degree angle featuring seaweed green and stone blue gradients with hints of amber organic curved shapes representing data flow high-quality ultra-realistic cinematic 8K UHD high resolution sharp and detail

Getting Started with GoMock

First, let’s set up GoMock in your project:

Terminal window
go install github.com/golang/mock/mockgen@latest

Creating Your First Mock

Let’s say we have a simple interface for a user service:

type UserService interface {
GetUser(id string) (*User, error)
CreateUser(user *User) error
}

To generate a mock for this interface, use mockgen:

Terminal window
mockgen -source=user_service.go -destination=mocks/mock_user_service.go

Writing Tests with GoMock

Here’s a practical example of how to use GoMock in your tests:

func TestUserHandler_GetUser(t *testing.T) {
ctrl := gomock.NewController(t)
defer ctrl.Finish()
mockService := mocks.NewMockUserService(ctrl)
handler := NewUserHandler(mockService)
// Set up expectations
mockService.EXPECT().
GetUser("123").
Return(&User{ID: "123", Name: "John"}, nil)
user, err := handler.GetUser("123")
assert.NoError(t, err)
assert.Equal(t, "John", user.Name)
}

Rocky mountain peaks viewed from a diagonal perspective bathed in warm amber light during golden hour with stone blue sky gradients natural textures and formations highlighted high-quality ultra-realistic cinematic 8K UHD high resolution sharp and detail

Best Practices for Using GoMock

  1. Mock at Interface Boundaries: Create interfaces at your application’s boundaries and mock those instead of concrete implementations.

  2. Use Strict Mocking: Enable strict mocking to catch unexpected calls early:

ctrl := gomock.NewController(t)
mockService := NewMockService(ctrl)
  1. Test Edge Cases: Use GoMock to simulate error conditions and edge cases:
mockService.EXPECT().
GetUser(gomock.Any()).
Return(nil, errors.New("database error"))
  1. Match Arguments Flexibly: Use GoMock matchers for more flexible argument matching:
mockService.EXPECT().
CreateUser(gomock.Any()).
DoAndReturn(func(user *User) error {
// Custom validation logic
return nil
})

Improving Code Coverage

To maximize your test coverage with GoMock:

  1. Test both success and failure paths
  2. Verify mock expectations
  3. Use gomock.InOrder when sequence matters
  4. Test timeout scenarios using gomock.After

Remember that high code coverage doesn’t automatically mean good tests. Focus on testing business-critical paths and edge cases that could cause issues in production.

White flower boutique arrangement photographed from slightly above angle featuring maroon and stone blue accents natural lighting emphasizing texture and depth organic composition high-quality ultra-realistic cinematic 8K UHD high resolution sharp and detail

icons/logo-tid.svg Latest Blogs
Discover our top articles, selected to support the growth of your business.
https://imgproxy-landing-page.tillitsdone.com/sig/rs:fit:1200:630/plain/https%3A%2F%2Fcms-r2.tillitsdone.com%2Fwp-content-prod%2Fuploads%2F2025%2F10%2FTill-its-done_SEO_R43_Sep_1440x697.jpg@webp สร้างเว็บไซต์ 1 เว็บ ต้องใช้งบเท่าไหร่? เจาะลึกทุกองค์ประกอบ website development cost อยากสร้างเว็บไซต์แต่ไม่มั่นใจในเรื่องของงบประมาณ อ่านสรุปเจาะลึกตั้งแต่ดีไซน์, ฟังก์ชัน และการดูแล พร้อมตัวอย่างงบจริงจาก Till it’s done ที่แผนชัด งบไม่บานปลายแน่นอน https://imgproxy-landing-page.tillitsdone.com/sig/rs:fit:1200:630/plain/https%3A%2F%2Fcms-r2.tillitsdone.com%2Fwp-content-prod%2Fuploads%2F2025%2F10%2FTill-its-done_SEO_R42_Sep_1440x697.jpg@webp Next.js สอน 14 ขั้นตอนเบื้องต้น: สร้างโปรเจกต์แรกใน 30 นาที เริ่มต้นกับ Next.js ใน 14 ขั้นตอนเพียงแค่ 30 นาที พร้อม SSR/SSG และ API Routes ด้วยตัวอย่างโค้ดง่าย ๆ อ่านต่อเพื่อสร้างโปรเจ็กต์แรกได้ทันทีที่นี่ https://imgproxy-landing-page.tillitsdone.com/sig/rs:fit:1200:630/plain/https%3A%2F%2Fcms-r2.tillitsdone.com%2Fwp-content-prod%2Fuploads%2F2025%2F10%2FTill-its-done_SEO_R41_Sep_1440x697.jpg@webp วิธีสมัคร Apple Developer Account เพื่อนำแอปขึ้น App Store ทีละขั้นตอน อยากปล่อยแอปบน App Store ระดับโลก มาอ่านคู่มือสมัคร Apple Developer Account พร้อมเคล็ดลับ TestFlight และวิธีอัปโหลดที่ง่ายในบทความเดียวนี้ได้เลย https://imgproxy-landing-page.tillitsdone.com/sig/rs:fit:1200:630/plain/https%3A%2F%2Fcms-r2.tillitsdone.com%2Fwp-content-prod%2Fuploads%2F2025%2F10%2FTill-its-done_SEO_R38_Sep_1440x697.jpg@webp TypeScript Interface คืออะไร? อธิบายพร้อมวิธีใช้และข้อแตกต่างจาก Type เรียนรู้วิธีใช้ TypeScript Interface เพื่อสร้างโครงสร้างข้อมูลที่ปลอดภัยและเข้าใจง่าย พร้อมเปรียบเทียบข้อดีข้อแตกต่างกับ Type ที่คุณต้องรู้ ถูกรวมเอาไว้ในบทความนี้แล้ว https://imgproxy-landing-page.tillitsdone.com/sig/rs:fit:1200:630/plain/https%3A%2F%2Fcms-r2.tillitsdone.com%2Fwp-content-prod%2Fuploads%2F2025%2F09%2FTill-its-done_SEO_R36_Sep_1440x697.jpg@webp Material-UI (MUI) คืออะไร อยากสร้าง UI สวยงามและเป็นมืออาชีพในเวลาอันรวดเร็วใช่ไหม มาทำความรู้จักกับ Material-UI (MUI) ที่ช่วยให้คุณพัฒนาแอปพลิเคชันบน React ได้ง่ายและดูดีในทุกอุปกรณ์ https://imgproxy-landing-page.tillitsdone.com/sig/rs:fit:1200:630/plain/https%3A%2F%2Fcms-r2.tillitsdone.com%2Fwp-content-prod%2Fuploads%2F2025%2F09%2FTill-its-done_SEO_R27_Sep_1440x697.jpg@webp เปรียบเทียบ 3 วิธีติดตั้ง install node js บน Ubuntu: NVM vs NodeSource vs Official Repo แบบไหนดีที่สุด? เรียนรู้วิธีติดตั้ง Node.js บน Ubuntu ด้วย NVM, NodeSource หรือ Official Repo เลือกวิธีที่เหมาะกับความต้องการของคุณ พร้อมเปรียบเทียบ เพื่อการพัฒนาที่มีประสิทธิภาพ!
icons/logo-tid.svg

Talk with CEO

Ready to bring your web/app to life or boost your team with expert Thai developers?
Contact us today to discuss your needs, and let’s create tailored solutions to achieve your goals. We’re here to help at every step!
🖐️ Contact us
down Explore our best articles, cover a wide variety of technologies
Our knowledge base
196 Articles
Explore right
icons/logo-react.svg ReactJs
Popular JavaScript library for building user interfaces with a component-based architecture.
160 Articles
Explore right
icons/flutter.svg Flutter
UI toolkit for building natively compiled applications for mobile, web, and desktop from a single codebase.
144 Articles
Explore right
icons/logo-nodejs.svg Nodejs
JavaScript runtime for building scalable, high-performance server-side applications.
58 Articles
Explore right
icons/next-js.svg Nextjs
React framework enabling server-side rendering and static site generation for optimized performance.
38 Articles
Explore right
icons/tailwind.svg TailwindCSS
Utility-first CSS framework for rapid UI development.
36 Articles
Explore right
icons/code-outline.svg Typescript
Superset of JavaScript adding static types for improved code quality and maintainability.
126 Articles
Explore right
icons/code-outline.svg Golang
Programming language known for its simplicity, concurrency model, and performance.
67 Articles
Explore right
icons/code-outline.svg AstroJs
Astro is an all-in-one web framework. It includes everything you need to create a website, built-in.
38 Articles
Explore right
icons/code-outline.svg Jest
Versatile testing framework for JavaScript applications supporting various test types.
16 Articles
Explore right
icons/code-outline.svg Website development th
11 Articles
Explore right
icons/code-outline.svg Mobile application th
5 Articles
Explore right
icons/code-outline.svg Reactjs th
4 Articles
Explore right
icons/code-outline.svg Nextjs th
3 Articles
Explore right
icons/code-outline.svg Flutter th
1 Articles
Explore right
icons/code-outline.svg Software house th
1 Articles
Explore right
icons/code-outline.svg Nodejs th
1 Articles
Explore right
icons/code-outline.svg Typescript th
337 Articles
Explore right
icons/css-4.svg CSS
CSS3 is the latest version of Cascading Style Sheets, offering advanced styling features like animations, transitions, shadows, gradients, and responsive design.
Let's keep in Touch
Thank you for your interest in Tillitsdone! Whether you have a question about our services, want to discuss a potential project, or simply want to say hello, we're here and ready to assist you.
We'll be right here with you every step of the way.
Contact Information
rick@tillitsdone.com+66824564755
Find All the Ways to Get in Touch with Tillitsdone - We're Just a Click, Call, or Message Away. We'll Be Right Here, Ready to Respond and Start a Conversation About Your Needs.
Address
9 Phahonyothin Rd, Khlong Nueng, Khlong Luang District, Pathum Thani, Bangkok Thailand
Visit Tillitsdone at Our Physical Location - We'd Love to Welcome You to Our Creative Space. We'll Be Right Here, Ready to Show You Around and Discuss Your Ideas in Person.
Social media
FacebookInstagramLinkedIn
Connect with Tillitsdone on Various Social Platforms - Stay Updated and Engage with Our Latest Projects and Insights. We'll Be Right Here, Sharing Our Journey and Ready to Interact with You.
We anticipate your communication and look forward to discussing how we can contribute to your business's success.
We'll be here, prepared to commence this promising collaboration.
Frequently Asked Questions
Explore frequently asked questions about our products and services.
Whether you're curious about features, warranties, or shopping policies, we provide comprehensive answers to assist you.