Make sure marks in subclasses don't change marks in superclasses

Fix #842

CHANGELOG

@@ -1,6 +1,10 @@
 2.7.3 (compared to 2.7.2)
 -----------------------------
 
+- fix issue842: applying markers in classes no longer propagate this markers
+  to superclasses which also have markers.
+  Thanks xmo-odoo for the report and Bruno Oliveira for the PR.
+
 - preserve warning functions after call to pytest.deprecated_call. Thanks
   Pieter Mulder for PR.
 

_pytest/mark.py

@@ -1,4 +1,5 @@
 """ generic mechanism for marking and selecting python functions. """
+import inspect
 import py
 
 
@@ -253,15 +254,17 @@ class MarkDecorator:
             otherwise add *args/**kwargs in-place to mark information. """
         if args and not kwargs:
             func = args[0]
-            if len(args) == 1 and (istestfunc(func) or
-                                   hasattr(func, '__bases__')):
-                if hasattr(func, '__bases__'):
+            is_class = inspect.isclass(func)
+            if len(args) == 1 and (istestfunc(func) or is_class):
+                if is_class:
                     if hasattr(func, 'pytestmark'):
-                        l = func.pytestmark
-                        if not isinstance(l, list):
-                            func.pytestmark = [l, self]
-                        else:
-                            l.append(self)
+                        mark_list = func.pytestmark
+                        if not isinstance(mark_list, list):
+                            mark_list = [mark_list]
+                        # always work on a copy to avoid updating pytestmark
+                        # from a superclass by accident
+                        mark_list = mark_list + [self]
+                        func.pytestmark = mark_list
                     else:
                         func.pytestmark = [self]
                 else:

testing/test_mark.py

@@ -369,6 +369,45 @@ class TestFunctional:
             print (item, item.keywords)
             assert 'a' in item.keywords
 
+    def test_mark_decorator_subclass_does_not_propagate_to_base(self, testdir):
+        p = testdir.makepyfile("""
+            import pytest
+
+            @pytest.mark.a
+            class Base: pass
+
+            @pytest.mark.b
+            class Test1(Base):
+                def test_foo(self): pass
+
+            class Test2(Base):
+                def test_bar(self): pass
+        """)
+        items, rec = testdir.inline_genitems(p)
+        self.assert_markers(items, test_foo=('a', 'b'), test_bar=('a',))
+
+    def test_mark_decorator_baseclasses_merged(self, testdir):
+        p = testdir.makepyfile("""
+            import pytest
+
+            @pytest.mark.a
+            class Base: pass
+
+            @pytest.mark.b
+            class Base2(Base): pass
+
+            @pytest.mark.c
+            class Test1(Base2):
+                def test_foo(self): pass
+
+            class Test2(Base2):
+                @pytest.mark.d
+                def test_bar(self): pass
+        """)
+        items, rec = testdir.inline_genitems(p)
+        self.assert_markers(items, test_foo=('a', 'b', 'c'),
+                            test_bar=('a', 'b', 'd'))
+
     def test_mark_with_wrong_marker(self, testdir):
         reprec = testdir.inline_runsource("""
                 import pytest
@@ -477,6 +516,22 @@ class TestFunctional:
         reprec = testdir.inline_run("-m", "mark1")
         reprec.assertoutcome(passed=1)
 
+    def assert_markers(self, items, **expected):
+        """assert that given items have expected marker names applied to them.
+        expected should be a dict of (item name -> seq of expected marker names)
+
+        .. note:: this could be moved to ``testdir`` if proven to be useful
+        to other modules.
+        """
+        from _pytest.mark import MarkInfo
+        items = dict((x.name, x) for x in items)
+        for name, expected_markers in expected.items():
+            markers = items[name].keywords._markers
+            marker_names = set([name for (name, v) in markers.items()
+                                if isinstance(v, MarkInfo)])
+            assert marker_names == set(expected_markers)
+
+
 class TestKeywordSelection:
     def test_select_simple(self, testdir):
         file_test = testdir.makepyfile("""