}
	})

	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))
		if _, err := tw.Write([]byte("Kilts")); err != ErrWriteTooLong {

		testReadFile(t, src.File[i], &wt)
	}

	// make a new zip file copying the old compressed data.
	buf2 := new(bytes.Buffer)
	dst := NewWriter(buf2)
	for _, f := range src.File {
		if err := dst.Copy(f); err != nil {
			t.Fatal(err)
		}
	}
	if err := dst.Close(); err != nil {
		t.Fatal(err)
	}

	// read the new one back
	r, err := NewReader(bytes.NewReader(buf2.Bytes()), int64(buf2.Len()))