type FakeCA struct {
	SignedCert    []byte
	SignErr       *caerror.Error
	KeyCertBundle *util.KeyCertBundle
	ReceivedIDs   []string
}

// Sign returns the SignErr if SignErr is not nil, otherwise, it returns SignedCert.
func (ca *FakeCA) Sign(csr []byte, certOpts ca.CertOpts) ([]byte, error) {
	ca.ReceivedIDs = certOpts.SubjectIDs
	if ca.SignErr != nil {
		return nil, ca.SignErr
	}
	return ca.SignedCert, nil
}