diff --git a/testdata/python/basic.py b/testdata/python/basic.py
index 0acb8c009..4c524342f 100644
--- a/testdata/python/basic.py
+++ b/testdata/python/basic.py
@@ -1011,7 +1011,7 @@ class BasicTest(unittest.TestCase):
       self.assertEqual( False, True )  # this must never hit
     except Exception as e:
       err = str(e)
-    self.assertEqual( err, "Unexpected object type (expected argument of class A, got X) in B.b4" );
+    self.assertEqual( err, "Unexpected object type (expected argument of class A, got X) for argument #1 in B.b4" );
   
     # Test, if this throws an error (object of class X passed to A argument):
     err = ""
@@ -1022,7 +1022,7 @@ class BasicTest(unittest.TestCase):
       self.assertEqual( False, True )  # this must never hit
     except Exception as e:
       err = str(e)
-    self.assertEqual( err, "Unexpected object type (expected argument of class A, got B) in B.b4" );
+    self.assertEqual( err, "Unexpected object type (expected argument of class A, got B) for argument #1 in B.b4" );
   
   def test_17(self):
 
diff --git a/testdata/ruby/basic_testcore.rb b/testdata/ruby/basic_testcore.rb
index de8e911b3..87f2f1e4b 100644
--- a/testdata/ruby/basic_testcore.rb
+++ b/testdata/ruby/basic_testcore.rb
@@ -925,7 +925,7 @@ class Basic_TestClass < TestBase
       assert_equal( b.b4( Y.new ), "b4_result: -6" )
       assert_equal( false, true )  # this must never hit
     rescue
-      assert_equal( $!.to_s(), "Unexpected object type (expected argument of class A, got Basic_TestClass::Y) in B::b4" );
+      assert_equal( $!.to_s(), "Unexpected object type (expected argument of class A, got Basic_TestClass::Y) for argument #1 in B::b4" );
     end
   
     # Test, if this throws an error (object of class X passed to A argument):
@@ -935,7 +935,7 @@ class Basic_TestClass < TestBase
       assert_equal( b.b4( bb ), "b4_result: -6" )
       assert_equal( false, true )  # this must never hit
     rescue
-      assert_equal( $!.to_s(), "Unexpected object type (expected argument of class A, got RBA::B) in B::b4" );
+      assert_equal( $!.to_s(), "Unexpected object type (expected argument of class A, got RBA::B) for argument #1 in B::b4" );
     end
   
   end