Writing Basic Tests in Go

Snippet

Writing Basic Tests in Go

Go has built-in testing support through the testing package. Test files are named with _test.go suffix. Test functions start with Test prefix and receive a *testing.T argument. The t.Errorf() method marks a test as failed while allowing execution to continue. Use t.Run() for subtests to organize related test cases cleanly.

snippet.go
go
package main
 
import "testing"
 
func Add(a, b int) int {
    return a + b
}
 
func TestAdd(t *testing.T) {
    result := Add(2, 3)
    expected := 5
 
    if result != expected {
        t.Errorf("Add(2, 3) = %d, expected %d", result, expected)
    }
}
 
func TestAddNegative(t *testing.T) {
    result := Add(-5, 3)
    expected := -2
 
    if result != expected {
        t.Errorf("Add(-5, 3) = %d, expected %d", result, expected)
    }
}

Breakdown

func TestAdd(t *testing.T)

Test function receives testing.T parameter - t parameter controls test execution

t.Errorf("...", result, expected)

Errorf logs failure message without stopping test execution

t.Run("subtest name", func(t *testing.T) { })

Subtests using t.Run() group related test cases with descriptive names

testing.T

Testing.T type provides methods for logging and controlling test flow

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