code: func AssertCertificateHasCommonName(t *testing.T, cert *x509.Certificate, commonName string) {
  	if cert.Subject.CommonName != commonName {
  		t.Errorf("cert has Subject.CommonName %s, expected %s", cert.Subject.CommonName, commonName)
  	}
  }
docs: // AssertCertificateHasCommonName is a utility function for kubeadm testing that asserts if a given certificate has
  // the expected SubjectCommonName