code: func (sa *StorageAuthority) GetCertificate(_ context.Context, serial string) (core.Certificate, error) {
  	// Serial ee == 238.crt
  	if serial == "0000000000000000000000000000000000ee" {
  		certPemBytes, _ := ioutil.ReadFile("test/238.crt")
  		certBlock, _ := pem.Decode(certPemBytes)
  		return core.Certificate{
  			RegistrationID: 1,
  			DER:            certBlock.Bytes,
  		}, nil
  	} else if serial == "0000000000000000000000000000000000b2" {
  		certPemBytes, _ := ioutil.ReadFile("test/178.crt")
  		certBlock, _ := pem.Decode(certPemBytes)
  		return core.Certificate{
  			RegistrationID: 1,
  			DER:            certBlock.Bytes,
  		}, nil
  	} else {
  		return core.Certificate{}, errors.New("No cert")
  	}
  }
docs: // GetCertificate is a mock