Testing in Go – Writing Unit Tests and Benchmarks (Table-Driven)

Writing a Basic Test

Go's built-in testing package requires test files to end in _test.go and test functions to start with Test.

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

Table-Driven Tests

A common Go idiom for testing multiple input/output combinations concisely.

func TestAddTable(t *testing.T) {
    cases := []struct {
        a, b, expected int
    }{
        {1, 2, 3},
        {5, 5, 10},
        {-1, 1, 0},
    }
    for _, c := range cases {
        result := Add(c.a, c.b)
        if result != c.expected {
            t.Errorf("Add(%d, %d) = %d; want %d", c.a, c.b, result, c.expected)
        }
    }
}

Writing Benchmarks

func BenchmarkAdd(b *testing.B) {
    for i := 0; i < b.N; i++ {
        Add(2, 3)
    }
}

Run tests with go test and benchmarks with go test -bench=.