diff --git a/testing/python/metafunc.py b/testing/python/metafunc.py
index ce84f7a57..afce579e6 100644
--- a/testing/python/metafunc.py
+++ b/testing/python/metafunc.py
@@ -21,6 +21,7 @@ class TestMetafunc:
         metafunc = self.Metafunc(function)
         assert not metafunc.fixturenames
         repr(metafunc._calls)
+        assert funcargs._format_args(function) == '()'
 
     def test_function_basic(self):
         def func(arg1, arg2="qwe"): pass
@@ -29,6 +30,7 @@ class TestMetafunc:
         assert 'arg1' in metafunc.fixturenames
         assert metafunc.function is func
         assert metafunc.cls is None
+        assert funcargs._format_args(func) == "(arg1, arg2='qwe')"
 
     def test_addcall_no_args(self):
         def func(arg1): pass
@@ -38,6 +40,7 @@ class TestMetafunc:
         call = metafunc._calls[0]
         assert call.id == "0"
         assert not hasattr(call, 'param')
+        assert funcargs._format_args(func) == "(arg1)"
 
     def test_addcall_id(self):
         def func(arg1): pass
@@ -85,6 +88,7 @@ class TestMetafunc:
         metafunc.parametrize("y", [1,2])
         pytest.raises(ValueError, lambda: metafunc.parametrize("y", [5,6]))
         pytest.raises(ValueError, lambda: metafunc.parametrize("y", [5,6]))
+        assert funcargs._format_args(func) == '(x, y)'
 
     def test_parametrize_and_id(self):
         def func(x, y): pass