[utils][tests][dir2] Improve test_misbehaving_object_without_trait_names

IPython/utils/tests/test_dir2.py

@@ -1,58 +1,67 b''
 from IPython.utils.dir2 import dir2
 
+import pytest
+
 
 class Base(object):
     x = 1
     z = 23
 
 
 def test_base():
     res = dir2(Base())
     assert "x" in res
     assert "z" in res
     assert "y" not in res
     assert "__class__" in res
     assert res.count("x") == 1
     assert res.count("__class__") == 1
 
 
 def test_SubClass():
 
     class SubClass(Base):
         y = 2
 
     res = dir2(SubClass())
     assert "y" in res
     assert res.count("y") == 1
     assert res.count("x") == 1
 
 
 def test_SubClass_with_trait_names_attr():
     # usecase: trait_names is used in a class describing psychological classification
 
     class SubClass(Base):
         y = 2
         trait_names = 44
 
     res = dir2(SubClass())
-    assert('trait_names' in res)
+    assert "trait_names" in res
 
 
 def test_misbehaving_object_without_trait_names():
     # dir2 shouldn't raise even when objects are dumb and raise
     # something other than AttribteErrors on bad getattr.
 
-    class MisbehavingGetattr(object):
-        def __getattr__(self):
+    class MisbehavingGetattr:
+        def __getattr__(self, attr):
             raise KeyError("I should be caught")
 
         def some_method(self):
-            pass
+            return True
 
     class SillierWithDir(MisbehavingGetattr):
         def __dir__(self):
             return ['some_method']
 
     for bad_klass in (MisbehavingGetattr, SillierWithDir):
-        res = dir2(bad_klass())
-        assert('some_method' in res)
+        obj = bad_klass()
+
+        assert obj.some_method()
+
+        with pytest.raises(KeyError):
+            obj.other_method()
+
+        res = dir2(obj)
+        assert "some_method" in res