diff --git a/blas/testblas/level1double.go b/blas/testblas/level1double.go
index c83a9131..fb98b5c4 100644
--- a/blas/testblas/level1double.go
+++ b/blas/testblas/level1double.go
@@ -1434,7 +1434,7 @@ func IdamaxTest(t *testing.T, blasser Idamaxer) {
 			if floats.HasNaN(c.X) {
 				t.Log(s)
 			} else {
-				t.Errorf(s)
+				t.Error(s)
 			}
 		}
 	}
diff --git a/optimize/unconstrained_test.go b/optimize/unconstrained_test.go
index e66f4a4a..702afa31 100644
--- a/optimize/unconstrained_test.go
+++ b/optimize/unconstrained_test.go
@@ -1350,7 +1350,7 @@ func TestNelderMeadOneD(t *testing.T) {
 	var s *Settings
 	result, err := Minimize(p, x, s, m)
 	if err != nil {
-		t.Errorf(err.Error())
+		t.Fatalf("could not minimize: %v", err)
 	}
 	if !floats.EqualApprox(result.X, []float64{0}, 1e-10) {
 		t.Errorf("Minimum not found")