if err != nil {
		return nil, err
	}
	return x509.ParseCertificate(certDERBytes)
}

// RemoveDuplicateAltNames removes duplicate items in altNames.
func RemoveDuplicateAltNames(altNames *certutil.AltNames) {
	if altNames == nil {
		return
	}

	if altNames.DNSNames != nil {
		altNames.DNSNames = sets.List(sets.New(altNames.DNSNames...))
	}

			},
			&certutil.AltNames{
				DNSNames: []string{"a"},
				IPs:      []net.IP{{127, 0, 0, 1}},
			},
		},
	}
	for _, tt := range tests {
		RemoveDuplicateAltNames(tt.args)
		if !reflect.DeepEqual(tt.args, tt.want) {
			t.Errorf("Wanted %v, got %v", tt.want, tt.args)
		}
	}
}

func TestVerifyCertChain(t *testing.T) {
	tmpdir, err := os.MkdirTemp("", "")