t.Errorf("parsePAXRecord(%q): got (%q: %q), want (%q: %q)",
				v.in, key, val, v.wantKey, v.wantVal)
		}
		if res != v.wantRes {
			t.Errorf("parsePAXRecord(%q): got residual %q, want residual %q",
				v.in, res, v.wantRes)
		}
	}
}

func TestFormatPAXRecord(t *testing.T) {
	medName := strings.Repeat("CD", 50)
	longName := strings.Repeat("AB", 100)

	vectors := []struct {

	// headers since 0.0 headers were not PAX compliant.
	var sparseMap []string

	paxHdrs := make(map[string]string)
	for len(sbuf) > 0 {
		key, value, residual, err := parsePAXRecord(sbuf)
		if err != nil {
			return nil, ErrHeader
		}
		sbuf = residual

		switch key {
		case paxGNUSparseOffset, paxGNUSparseNumBytes:
			// Validate sparse header order and value.