Don't be fooled by a class named test_something. Fixes #829

3 files changed, 12 insertions, 2 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index 9eace5d2..8833c0d0 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -20,7 +20,10 @@ development at the same time, like 4.5.x and 5.0.
 Unreleased
 ----------
 
-- Nothing yet.
+- A class named "test_something" no longer confuses the `test_function` dynamic
+  context setting.  Fixes `issue 829`_.
+
+.. _issue 829: https://github.com/nedbat/coveragepy/issues/829
 
 
 .. _changes_50a6:
diff --git a/coverage/context.py b/coverage/context.py
index 903fc51b..ea13da21 100644
--- a/coverage/context.py
+++ b/coverage/context.py
@@ -52,7 +52,9 @@ def qualname_from_frame(frame):
         method = getattr(self, fname, None)
 
     if method is None:
-        func = frame.f_globals[fname]
+        func = frame.f_globals.get(fname)
+        if func is None:
+            return None
         return func.__module__ + '.' + fname
 
     func = getattr(method, '__func__', None)
diff --git a/tests/test_context.py b/tests/test_context.py
index 5d40e339..21d29a0c 100644
--- a/tests/test_context.py
+++ b/tests/test_context.py
@@ -285,3 +285,8 @@ class QualnameTest(CoverageTest):
             self.skipTest("Old-style classes are only in Python 2")
         self.assertEqual(OldStyle().meth(), "tests.test_context.OldStyle.meth")
         self.assertEqual(OldChild().meth(), "tests.test_context.OldStyle.meth")
+
+    def test_bug_829(self):
+        # A class with a name like a function shouldn't confuse qualname_from_frame.
+        class test_something(object):
+            self.assertEqual(get_qualname(), None)