How to Write Unit Tests in Go with testing Package

Write a function with the testing.T parameter in a file named *_test.go and run it with go test.

package mypackage

import "testing"

func TestAdd(t *testing.T) {
    got := Add(2, 3)
    want := 5
    if got != want {
        t.Errorf("Add(2, 3) = %d; want %d", got, want)
    }
}

Run the test:

go test

Unit tests are small checks that verify your code works correctly. You write them in files ending with _test.go so the Go tool knows to run them. It's like a checklist that automatically runs every time you save your code to catch mistakes early.