t.Fatalf("Write() = %v, want %v", err, ErrWriteTooLong)
		}
	})

	t.Run("NegativeSize", func(t *testing.T) {
		tw := NewWriter(new(bytes.Buffer))
		hdr := &Header{Name: "small.txt", Size: -1}
		if err := tw.WriteHeader(hdr); err == nil {
			t.Fatalf("WriteHeader() = nil, want non-nil error")
		}
	})

	t.Run("BeforeHeader", func(t *testing.T) {
		tw := NewWriter(new(bytes.Buffer))

		for j := 0; j < 3; j++ {
			w, _ := zw.CreateHeader(&FileHeader{
				Name:   "foo",
				Method: Deflate,
			})
			w.Write(bigBuf)
		}
		zw.Close()
	}

	b.ReportAllocs()
	// Run once and then reset the timer.
	// This effectively discards the very large initial flate setup cost,
	// as well as the initialization of bigBuf.
	runOnce(&bytes.Buffer{})
	b.ResetTimer()