if err != ErrFormat {
		t.Fatalf("unexpected error, got: %v, want: %v", err, ErrFormat)
	}

	// Also check that an archive containing a handful of empty
	// files doesn't cause an issue
	b := bytes.NewBuffer(nil)
	w := NewWriter(b)
	for i := 0; i < 5; i++ {
		_, err := w.Create("")
		if err != nil {
			t.Fatalf("Writer.Create failed: %s", err)
		}
	}
	if err := w.Close(); err != nil {

			if err != nil {
				b.Fatal(err)
			}
			b.SetBytes(int64(len(f)))
			b.ReportAllocs()
			b.ResetTimer()
			var record sql.Record
			for i := 0; i < b.N; i++ {
				r := NewReader(io.NopCloser(bytes.NewBuffer(f)), &ReaderArgs{})
				for {
					record, err = r.Read(record)
					if err != nil {
						break
					}
				}
				r.Close()
				if err != io.EOF {

		}
		tt.f(reader)
		err := reader.UnreadRune()
		if err == nil {
			t.Errorf("Unreading after %s: expected error", tt.name)
		}
	}
}

func TestReaderDoubleUnreadRune(t *testing.T) {
	buf := NewBuffer([]byte("groucho"))
	if _, _, err := buf.ReadRune(); err != nil {
		// should not happen
		t.Fatal(err)
	}
	if err := buf.UnreadByte(); err != nil {
		// should not happen
		t.Fatal(err)
	}