update test

Author: liamsi

impl/monitor/monitor.go

@@ -56,6 +56,9 @@ var (
 	// ErrInvalidSignature occurs when the signature on the observed map root is
 	// invalid.
 	ErrInvalidSignature = errors.New("Recreated root does not match")
+	// ErrNothingProcessed occurs when the monitor did not process any mutations /
+	// smrs yet.
+	ErrNothingProcessed = errors.New("did not process any mutations yet")
 )
 
 // Server holds internal state for the monitor server.
@@ -105,7 +108,7 @@ func (s *Server) GetSignedMapRoot(ctx context.Context, in *ktpb.GetMonitoringReq
 	if len(s.proccessedSMRs) > 0 {
 		return s.proccessedSMRs[len(s.proccessedSMRs)-1], nil
 	}
-	return nil, errors.New("did not process any mutations yet")
+	return nil, ErrNothingProcessed
 }
 
 // GetSignedMapRootStream is a streaming API similar to GetSignedMapRoot.

impl/monitor/monitor_test.go

@@ -28,7 +28,7 @@ import (
 func TestGetSignedMapRoot(t *testing.T) {
 	srv := Server{}
 	_, err := srv.GetSignedMapRoot(context.TODO(), nil)
-	if got, want := grpc.Code(err), codes.OK; got != want {
+	if got, want := err, ErrNothingProcessed; got != want {
 		t.Errorf("GetSignedMapRoot(_, _): %v, want %v", got, want)
 	}
 }