h, err := rs.ToHeader()
		if err != nil && !testCase.errExpected || err == nil && testCase.errExpected {
			t.Errorf("expected error with invalid range: %v", err)
		}
		if h != testCase.spec {
			t.Errorf("Case %d: translated to incorrect header: %s expected: %s",
				i, h, testCase.spec)
		}
	}