Fuzz Testing Example

48dbfb9ece69e4cc31f8bf0c08dce25ed21b995f33d7a508677067e4f11b1523

go test fuzz v1
int(-42)
string("hello")

fuzz_test.go

func Foo(i int, s string) (string, error) {
        if i%7 == 0 && s == "hello" {
                return s, fmt.Errorf("error")
        }
        return fmt.Sprintf("%d: %s", i, s), nil
}

func FuzzFoo(f *testing.F) {
        f.Add(5, "hello") // Seed corpus addition

        f.Fuzz(func(t *testing.T, i int, s string) {
                out, err := Foo(i, s)
                if err != nil && out != "" {
                        t.Errorf("Foo(%v, %v) returned error %v", i, s, err)
                }
        })
}