diff --git a/sm2/sm2_test.go b/sm2/sm2_test.go
index 3abbd582..b3071dbf 100644
--- a/sm2/sm2_test.go
+++ b/sm2/sm2_test.go
@@ -640,7 +640,7 @@ func TestEqual(t *testing.T) {
 		t.Errorf("private.Public() is not Equal to public: %q", public)
 	}
 	if !private.Equal(private) {
-		t.Errorf("private key is not equal to itself")
+		t.Errorf("private key is not equal to itself: %q", private.PrivateKey)
 	}
 
 	otherPriv, _ := GenerateKey(rand.Reader)
diff --git a/smx509/equal_test.go b/smx509/equal_test.go
index a27c5ebe..d605aa3f 100644
--- a/smx509/equal_test.go
+++ b/smx509/equal_test.go
@@ -19,7 +19,7 @@ func TestEqual(t *testing.T) {
 		t.Errorf("private.Public() is not Equal to public: %q", public)
 	}
 	if !private.Equal(private) {
-		t.Errorf("private key is not equal to itself")
+		t.Errorf("private key is not equal to itself: %q", private.PrivateKey)
 	}
 
 	enc, err := MarshalPKCS8PrivateKey(private)