merging pedronis-branch changes to resolve issue 15 for now.

This introduces py.test.collect._fillfuncargs which can
operate on Function like objects.

--HG--
branch : trunk

py/__init__.py

@@ -89,6 +89,7 @@ initpkg(__name__,
     'test.collect.Instance'  : ('./test/pycollect.py', 'Instance'),
     'test.collect.Generator' : ('./test/pycollect.py', 'Generator'),
     'test.collect.Function'  : ('./test/pycollect.py', 'Function'),
+    'test.collect._fillfuncargs' : ('./test/funcargs.py', 'fillfuncargs'),
 
     # thread related API (still in early design phase)
     '_thread.WorkerPool'      : ('./thread/pool.py', 'WorkerPool'),

py/test/funcargs.py

@@ -95,7 +95,7 @@ class FuncargRequest:
     def _fillfuncargs(self):
         argnames = getfuncargnames(self.function)
         if argnames:
-            assert not self._pyfuncitem._args, "yielded functions cannot have funcargs" 
+            assert not getattr(self._pyfuncitem, '_args', None), "yielded functions cannot have funcargs" 
         for argname in argnames:
             if argname not in self._pyfuncitem.funcargs:
                 self._pyfuncitem.funcargs[argname] = self.getfuncargvalue(argname)

py/test/testing/test_funcargs.py

@@ -79,6 +79,17 @@ class TestFillFuncArgs:
             "*1 passed*"
         ])
 
+    def test_fillfuncargs_exposed(self, testdir):
+        item = testdir.getitem("def test_func(some, other=42): pass")
+        class Provider:
+            def pytest_funcarg__some(self, request):
+                return request.function.__name__
+        item.config.pluginmanager.register(Provider())
+        if hasattr(item, '_args'):
+            del item._args
+        py.test.collect._fillfuncargs(item)
+        assert len(item.funcargs) == 1
+
 class TestRequest:
     def test_request_attributes(self, testdir):
         item = testdir.getitem("""