How do you write tests in Go?

Q: How do you write tests in Go?

Learn the answer to "How do you write tests in Go?" with detailed explanations, code examples, and best practices on DeployU.

The Scenario

You are a backend engineer at a fintech company. You are writing a new service that needs to be well-tested.

You need to write unit tests, integration tests, and benchmarks for your code.

The Challenge

Explain how you would write tests in Go. What are the key features of the Go testing framework, and how would you use them to write different types of tests?

Wrong Approach

A junior engineer might not be aware of the built-in testing framework in Go. They might try to write their own testing framework, which would be a waste of time. They might also not be aware of the different types of tests and when to use each one.

Addresses symptoms, not root cause

Right Approach

A senior engineer would know that Go has a powerful built-in testing framework. They would be able to explain how to use the `testing` package to write unit tests, integration tests, and benchmarks.

Step 1: Understand the `testing` Package

The testing package is a built-in package in Go that provides support for testing.

Feature	Description
`testing.T`	A type passed to Test functions to manage test state and support formatted test logs.
`t.Run()`	Used to create subtests.
`t.Error()`	Used to report a test failure.
`t.Fatal()`	Used to report a test failure and stop the test.
`testing.B`	A type passed to Benchmark functions to manage benchmark state and run the benchmark.

Step 2: Write a Unit Test

Here’s how we can write a simple unit test:

// main_test.go
package main

import "testing"

func TestMyFunction(t *testing.T) {
    // ... (your test code) ...
}

To run the tests, you can use the go test command.

Step 3: Write an Integration Test

You can use build tags to separate your integration tests from your unit tests.

// +build integration

package main

import "testing"

func TestMyIntegration(t *testing.T) {
    // ... (your integration test code) ...
}

To run the integration tests, you can use the go test -tags=integration command.

Step 4: Write a Benchmark

Here’s how we can write a simple benchmark:

// main_test.go
package main

import "testing"

func BenchmarkMyFunction(b *testing.B) {
    for i := 0; i < b.N; i++ {
        MyFunction()
    }
}

To run the benchmarks, you can use the go test -bench=. command.

Systematic, production-ready debugging

Practice Question

You want to run only the integration tests in your project. Which of the following commands would you use?

Questions