Factor out _safe_isclass

Author: blueyed

src/_pytest/python.py

@@ -188,18 +188,21 @@ def pytest_pycollect_makemodule(path, parent):
     return Module(path, parent)
 
 
+def _safe_isclass(obj):
+    try:
+        return isclass(obj)
+    except Exception:
+        return False
+
+
 @hookimpl(hookwrapper=True)
 def pytest_pycollect_makeitem(collector, name, obj):
     outcome = yield
     res = outcome.get_result()
     if res is not None:
         return
     # nothing was collected elsewhere, let's do it here
-    try:
-        is_class = isclass(obj)
-    except Exception:
-        is_class = False
-    if is_class:
+    if _safe_isclass(obj):
         if collector.istestclass(obj, name):
             Class = collector._getcustomclass("Class")
             outcome.force_result(Class(name, parent=collector))

testing/test_collection.py

@@ -1004,3 +1004,21 @@ def test_1():
     result = testdir.runpytest()
     assert result.ret == 0
     result.stdout.fnmatch_lines(["*1 passed in*"])
+
+
+def test__safe_isclass():
+    from _pytest.python import _safe_isclass
+
+    assert _safe_isclass(type) is True
+
+    # Simulates Django's django.conf.settings.
+    class ImproperlyConfigured(Exception):
+        pass
+
+    class RaisesOnGetAttr(object):
+        def raises(self):
+            raise ImproperlyConfigured
+
+        __class__ = property(raises)
+
+    assert _safe_isclass(RaisesOnGetAttr()) is False