Old-style classes can report the test_function name. #797

3 files changed, 24 insertions, 1 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index cae6e2d7..dbb9f74c 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -19,6 +19,10 @@ Unreleased
 - Dynamic contexts can now be determined by third-party code in a plugin.
   Thanks, Justas Sadzevičius.
 
+- the ``dynamic_context = test_function`` setting now works with Python 2
+  old-style classes, though it only reports the method name, not the class it
+  was defined on.  Closes `issue 797`_.
+
 - ``fail_under`` values more than 100 are reported as errors.  Thanks to Mike
   Fiedler for closing `issue 746`_.
 
@@ -46,6 +50,7 @@ Unreleased
 .. _issue 746: https://github.com/nedbat/coveragepy/issues/746
 .. _issue 748: https://github.com/nedbat/coveragepy/issues/748
 .. _issue 761: https://github.com/nedbat/coveragepy/issues/761
+.. _issue 797: https://github.com/nedbat/coveragepy/issues/797
 
 
 .. _changes_50a4:
diff --git a/coverage/context.py b/coverage/context.py
index 22c0e531..13800337 100644
--- a/coverage/context.py
+++ b/coverage/context.py
@@ -65,7 +65,7 @@ def qualname_from_frame(frame):
     if hasattr(func, '__qualname__'):
         qname = func.__qualname__
     else:
-        for cls in self.__class__.__mro__:
+        for cls in getattr(self.__class__, '__mro__', ()):
             f = cls.__dict__.get(fname, None)
             if f is None:
                 continue
diff --git a/tests/test_context.py b/tests/test_context.py
index 1b50d30d..ddbf59a3 100644
--- a/tests/test_context.py
+++ b/tests/test_context.py
@@ -228,6 +228,18 @@ def fake_out(self):                     # pylint: disable=missing-docstring, unu
 def patch_meth(self):                   # pylint: disable=missing-docstring, unused-argument
     return get_qualname()
 
+# pylint: disable=missing-docstring
+
+class OldStyle:                         # pylint: disable=old-style-class
+    def meth(self):
+        return get_qualname()
+
+class OldChild(OldStyle):
+    pass
+
+# pylint: enable=missing-docstring
+
+
 class QualnameTest(CoverageTest):
     """Tests of qualname_from_frame."""
 
@@ -262,3 +274,9 @@ class QualnameTest(CoverageTest):
         c = Child()
         c.meth = patch_meth
         self.assertEqual(c.meth(c), "patch_meth")
+
+    def test_oldstyle(self):
+        if not env.PY2:
+            self.skipTest("Old-style classes are only in Python 2")
+        self.assertEqual(OldStyle().meth(), "meth")
+        self.assertEqual(OldChild().meth(), "meth")