hdr     Header
			wantErr error
		}
		testWrite struct { // Write(str) == (wantCnt, wantErr)
			str     string
			wantCnt int
			wantErr error
		}
		testReadFrom struct { // ReadFrom(testFile{ops}) == (wantCnt, wantErr)
			ops     fileOps
			wantCnt int64
			wantErr error
		}
		testClose struct { // Close() == wantErr
			wantErr error
		}

		t.Fatalf("unexpected CreateHeader error: %v", err)
	}
	if err := w.Close(); err != nil {
		t.Fatalf("unexpected Close error: %v", err)
	}

	want, err := os.ReadFile("testdata/time-go.zip")
	if err != nil {
		t.Fatalf("unexpected ReadFile error: %v", err)
	}
	if got := buf.Bytes(); !bytes.Equal(got, want) {
		fmt.Printf("%x\n%x\n", got, want)
		t.Error("contents of time-go.zip differ")
	}
}