remove support for @pytest.fixture on classes, to be reserved for future use:

Fixture-classes could offer setup/teardown/addoption/configure methods
and provide higher level support.  Preliminary allowing it to work on classes
may make introducing it harder.

_pytest/python.py

@@ -17,6 +17,8 @@ class FixtureFunctionMarker:
         self.autoactive = autoactive
 
     def __call__(self, function):
+        if inspect.isclass(function):
+            raise ValueError("class fixtures not supported (may be in the future)")
         function._pytestfixturefunction = self
         return function
 
@@ -43,7 +45,7 @@ def fixture(scope="function", params=None, autoactive=False):
                 can see it.  If False (the default) then an explicit
                 reference is needed to activate the fixture.
     """
-    if hasattr(scope, "__call__") and params is None and autoactive == False:
+    if py.builtin.callable(scope) and params is None and autoactive == False:
         # direct decoration
         return FixtureFunctionMarker("function", params, autoactive)(scope)
     else:
@@ -1563,10 +1565,8 @@ class FixtureDef:
 
 def getfuncargnames(function, startindex=None):
     # XXX merge with main.py's varnames
-    if inspect.isclass(function):
-        function = function.__init__
-        startindex = 1
-    elif startindex is None:
+    #assert not inspect.isclass(function)
+    if startindex is None:
         startindex = inspect.ismethod(function) and 1 or 0
     argnames = inspect.getargs(py.code.getrawcode(function))[0]
     defaults = getattr(function, 'func_defaults',

doc/en/fixture.txt

@@ -569,8 +569,7 @@ self-contained implementation of this idea::
     
     import pytest
 
-    @pytest.fixture(scope="module")
-    class db:
+    class DB:
         def __init__(self):
             self.intransaction = []
         def begin(self, name):
@@ -578,6 +577,10 @@ self-contained implementation of this idea::
         def rollback(self):
             self.intransaction.pop()
 
+    @pytest.fixture(scope="module")
+    def db():
+        return DB()
+
     class TestClass:
         @pytest.fixture(autoactive=True)
         def transact(self, request, db):
@@ -590,9 +593,9 @@ self-contained implementation of this idea::
         def test_method2(self, db):
             assert db.intransaction == ["test_method2"]
 
-The class-level ``transact`` fixture is marked with *autoactive=true* which implies
-that all test methods in the class will use this fixture without a need to 
-specify it.
+The class-level ``transact`` fixture is marked with *autoactive=true*
+which implies that all test methods in the class will use this fixture
+without a need to specify it.
 
 If we run it, we get two passing tests::
 
@@ -614,11 +617,10 @@ And here is how autoactive fixtures work in other scopes:
   a global fixture should always quickly determine if it should do
   any work and avoid expensive imports or computation otherwise.
 
-Note that the above ``transact`` fixture may very well be something that
-you want to make available in your project but which requires an explicit using
-reference to have it activated.  The canonical way to do that is to put
-the transact definition into a conftest.py file without using
-``autoactive``::
+Note that the above ``transact`` fixture may very well be a fixture that
+you want to make available in your project without having it generally
+active.  The canonical way to do that is to put the transact definition 
+into a conftest.py file without using ``autoactive``::
 
     # content of conftest.py
     @pytest.fixture()
@@ -626,15 +628,16 @@ the transact definition into a conftest.py file without using
         db.begin()
         request.addfinalizer(db.rollback)
 
-and then have a TestClass using it by declaring the need::
+and then e.g. have a TestClass using it by declaring the need::
 
     @pytest.mark.usefixtures("transact")
     class TestClass:
         def test_method1(self):
             ...
 
-While all test methods in this TestClass will use the transaction
-fixture, other test classes or function will not do so without a marker or funcarg.
+All test methods in this TestClass will use the transaction fixture while
+other test classes or functions will not do so unless they also add
+a ``transact`` reference.
 
 controlled visibility of fixture functions
 ----------------------------------------------------

testing/test_python.py

@@ -547,10 +547,6 @@ def test_getfuncargnames():
     if sys.version_info < (3,0):
         assert funcargs.getfuncargnames(A.f) == ['arg1']
 
-    class A:
-        def __init__(self, x):
-            pass
-    assert funcargs.getfuncargnames(A) == ["x"]
 
 class TestFillFixtures:
     def test_fillfuncargs_exposed(self):
@@ -1803,7 +1799,7 @@ class TestFixtureUsages:
             *fixture*'missing'*not found*
         """)
 
-    def test_factory_setup_as_classes(self, testdir):
+    def test_factory_setup_as_classes_fails(self, testdir):
         testdir.makepyfile("""
             import pytest
             class arg1:
@@ -1811,17 +1807,10 @@ class TestFixtureUsages:
                     self.x = 1
             arg1 = pytest.fixture()(arg1)
 
-            class MySetup:
-                def __init__(self, request, arg1):
-                    request.instance.arg1 = arg1
-            pytest.fixture(autoactive=True)(MySetup)
-
-            class TestClass:
-                def test_method(self):
-                    assert self.arg1.x == 1
         """)
         reprec = testdir.inline_run()
-        reprec.assertoutcome(passed=1)
+        l = reprec.getfailedcollections()
+        assert len(l) == 1
 
     def test_request_can_be_overridden(self, testdir):
         testdir.makepyfile("""