extend Metafunc and write a pytest_generate_tests hook on the funcarg manager

which discovers factories

_pytest/main.py

@@ -443,6 +443,19 @@ class FuncargManager:
         for plugin in plugins:
             self.pytest_plugin_registered(plugin)
 
+    def pytest_generate_tests(self, metafunc):
+        for argname in metafunc.funcargnames:
+            faclist = self.getfactorylist(argname, metafunc.parentid,
+                                          metafunc.function, raising=False)
+            if faclist is None:
+                continue # will raise at setup time
+            for fac in faclist:
+                marker = getattr(fac, "funcarg", None)
+                if marker is not None:
+                    params = marker.kwargs.get("params")
+                    if params is not None:
+                        metafunc.parametrize(argname, params, indirect=True)
+
     def _parsefactories(self, holderobj, nodeid):
         if holderobj in self._holderobjseen:
             return
@@ -456,11 +469,13 @@ class FuncargManager:
                 obj = getattr(holderobj, name)
                 faclist.append((nodeid, obj))
 
-    def getfactorylist(self, argname, nodeid, function):
+    def getfactorylist(self, argname, nodeid, function, raising=True):
         try:
             factorydef = self.arg2facspec[argname]
         except KeyError:
+            if raising:
                 self._raiselookupfailed(argname, function, nodeid)
+        else:
             return self._matchfactories(factorydef, nodeid)
 
     def _matchfactories(self, factorydef, nodeid):

_pytest/python.py

@@ -256,7 +256,7 @@ class PyCollector(PyobjMixin, pytest.Collector):
         clscol = self.getparent(Class)
         cls = clscol and clscol.obj or None
         transfer_markers(funcobj, cls, module)
-        metafunc = Metafunc(funcobj, config=self.config,
+        metafunc = Metafunc(funcobj, parentid=self.nodeid, config=self.config,
             cls=cls, module=module)
         gentesthook = self.config.hook.pytest_generate_tests
         extra = [module]
@@ -555,10 +555,12 @@ class CallSpec2(object):
 
 
 class Metafunc:
-    def __init__(self, function, config=None, cls=None, module=None):
+    def __init__(self, function, config=None, cls=None, module=None,
+                 parentid=""):
         self.config = config
         self.module = module
         self.function = function
+        self.parentid = parentid
         self.funcargnames = getfuncargnames(function,
                                             startindex=int(cls is not None))
         self.cls = cls
@@ -885,11 +887,6 @@ class FuncargRequest:
         self.funcargnames = getfuncargnames(self.function)
         self.parentid = pyfuncitem.parent.nodeid
 
-    def _discoverfactories(self):
-        for argname in self.funcargnames:
-            if argname not in self._funcargs:
-                self._getfaclist(argname)
-
     def _getfaclist(self, argname):
         faclist = self._name2factory.get(argname, None)
         if faclist is None:

testing/test_python.py

@@ -989,6 +989,7 @@ class TestMetafunc:
     def test_parametrize_functional(self, testdir):
         testdir.makepyfile("""
             def pytest_generate_tests(metafunc):
+                assert "test_parametrize_functional" in metafunc.parentid
                 metafunc.parametrize('x', [1,2], indirect=True)
                 metafunc.parametrize('y', [2])
             def pytest_funcarg__x(request):
@@ -1680,3 +1681,20 @@ class TestFuncargManager:
         """)
         reprec = testdir.inline_run("-s")
         reprec.assertoutcome(passed=1)
+
+class TestFuncargMarker:
+    def test_parametrize(self, testdir):
+        testdir.makepyfile("""
+            import pytest
+            @pytest.mark.funcarg(params=["a", "b", "c"])
+            def pytest_funcarg__arg(request):
+                return request.param
+            l = []
+            def test_param(arg):
+                l.append(arg)
+            def test_result():
+                assert l == list("abc")
+        """)
+        reprec = testdir.inline_run()
+        reprec.assertoutcome(passed=4)
+