package pkg import ( "bytes" "io" "io/ioutil" "testing" ) type countReadSeeker struct { // used_test io.ReadSeeker // used_test N int64 // used_test } func (rs *countReadSeeker) Read(buf []byte) (int, error) { // used_test n, err := rs.ReadSeeker.Read(buf) rs.N += int64(n) return n, err } func TestFoo(t *testing.T) { // used_test r := bytes.NewReader([]byte("Hello, world!")) cr := &countReadSeeker{ReadSeeker: r} ioutil.ReadAll(cr) if cr.N != 13 { t.Errorf("got %d, want 13", cr.N) } } var sink int // used_test func BenchmarkFoo(b *testing.B) { // used_test for i := 0; i < b.N; i++ { sink = fn() } } func fn() int { return 0 } // used_test