implement funcarg factory scope marker and ScopeMismatch detection

_pytest/python.py

@@ -886,6 +886,7 @@ class FuncargRequest:
         self._currentarg = None
         self.funcargnames = getfuncargnames(self.function)
         self.parentid = pyfuncitem.parent.nodeid
+        self.scope = "function"
 
     def _getfaclist(self, argname):
         faclist = self._name2factory.get(argname, None)
@@ -982,6 +983,9 @@ class FuncargRequest:
         try:
             val = cache[cachekey]
         except KeyError:
+            __tracebackhide__ = True
+            check_scope(self.scope, scope)
+            __tracebackhide__ = False
             val = setup()
             cache[cachekey] = val
             if teardown is not None:
@@ -1007,7 +1011,6 @@ class FuncargRequest:
         factorylist = self._getfaclist(argname)
         funcargfactory = factorylist.pop()
         node = self._pyfuncitem
-        oldarg = self._currentarg
         mp = monkeypatch()
         mp.setattr(self, '_currentarg', argname)
         try:
@@ -1016,11 +1019,24 @@ class FuncargRequest:
             pass
         else:
             mp.setattr(self, 'param', param, raising=False)
-        try:
-            self._funcargs[argname] = val = funcargfactory(request=self)
-            return val
-        finally:
-            mp.undo()
+
+        # implemenet funcarg marker scope
+        marker = getattr(funcargfactory, "funcarg", None)
+        scope = None
+        if marker is not None:
+            scope = marker.kwargs.get("scope")
+        if scope is not None:
+            __tracebackhide__ = True
+            check_scope(self.scope, scope)
+            __tracebackhide__ = False
+            mp.setattr(self, "scope", scope)
+            val = self.cached_setup(lambda: funcargfactory(request=self),
+                                    scope=scope)
+        else:
+            val = funcargfactory(request=self)
+        mp.undo()
+        self._funcargs[argname] = val
+        return val
 
     def _getscopeitem(self, scope):
         if scope == "function":
@@ -1039,7 +1055,7 @@ class FuncargRequest:
     def addfinalizer(self, finalizer):
         """add finalizer function to be called after test function
         finished execution. """
-        self._addfinalizer(finalizer, scope="function")
+        self._addfinalizer(finalizer, scope=self.scope)
 
     def _addfinalizer(self, finalizer, scope):
         colitem = self._getscopeitem(scope)
@@ -1049,3 +1065,15 @@ class FuncargRequest:
     def __repr__(self):
         return "<FuncargRequest for %r>" %(self._pyfuncitem)
 
+class ScopeMismatchError(Exception):
+    """ A funcarg factory tries to access a funcargvalue/factory
+    which has a lower scope (e.g. a Session one calls a function one)
+    """
+scopes = "session module class function".split()
+def check_scope(currentscope, newscope):
+    __tracebackhide__ = True
+    i_currentscope = scopes.index(currentscope)
+    i_newscope = scopes.index(newscope)
+    if i_newscope > i_currentscope:
+        raise ScopeMismatchError("You tried to access a %r scoped funcarg "
+            "from a %r scoped one." % (newscope, currentscope))

testing/test_python.py

@@ -58,7 +58,7 @@ class TestClass:
         ])
 
     def test_setup_teardown_class_as_classmethod(self, testdir):
-        testdir.makepyfile("""
+        testdir.makepyfile(test_mod1="""
             class TestClassMethod:
                 @classmethod
                 def setup_class(cls):
@@ -1698,3 +1698,110 @@ class TestFuncargMarker:
         reprec = testdir.inline_run()
         reprec.assertoutcome(passed=4)
 
+    def test_scope_session(self, testdir):
+        testdir.makepyfile("""
+            import pytest
+            l = []
+            @pytest.mark.funcarg(scope="module")
+            def pytest_funcarg__arg(request):
+                l.append(1)
+                return 1
+
+            def test_1(arg):
+                assert arg == 1
+            def test_2(arg):
+                assert arg == 1
+                assert len(l) == 1
+            class TestClass:
+                def test3(self, arg):
+                    assert arg == 1
+                    assert len(l) == 1
+        """)
+        reprec = testdir.inline_run()
+        reprec.assertoutcome(passed=3)
+
+    def test_scope_module_uses_session(self, testdir):
+        testdir.makepyfile("""
+            import pytest
+            l = []
+            @pytest.mark.funcarg(scope="module")
+            def pytest_funcarg__arg(request):
+                l.append(1)
+                return 1
+
+            def test_1(arg):
+                assert arg == 1
+            def test_2(arg):
+                assert arg == 1
+                assert len(l) == 1
+            class TestClass:
+                def test3(self, arg):
+                    assert arg == 1
+                    assert len(l) == 1
+        """)
+        reprec = testdir.inline_run()
+        reprec.assertoutcome(passed=3)
+
+    def test_scope_module_and_finalizer(self, testdir):
+        testdir.makeconftest("""
+            import pytest
+            finalized = []
+            created = []
+            @pytest.mark.funcarg(scope="module")
+            def pytest_funcarg__arg(request):
+                created.append(1)
+                assert request.scope == "module"
+                request.addfinalizer(lambda: finalized.append(1))
+            def pytest_funcarg__created(request):
+                return len(created)
+            def pytest_funcarg__finalized(request):
+                return len(finalized)
+        """)
+        testdir.makepyfile(
+            test_mod1="""
+                def test_1(arg, created, finalized):
+                    assert created == 1
+                    assert finalized == 0
+                def test_2(arg, created, finalized):
+                    assert created == 1
+                    assert finalized == 0""",
+            test_mod2="""
+                def test_3(arg, created, finalized):
+                    assert created == 2
+                    assert finalized == 1""",
+            test_mode3="""
+                def test_4(arg, created, finalized):
+                    assert created == 3
+                    assert finalized == 2
+            """)
+        reprec = testdir.inline_run()
+        reprec.assertoutcome(passed=4)
+
+    @pytest.mark.parametrize("method", [
+        'request.getfuncargvalue("arg")',
+        'request.cached_setup(lambda: None, scope="function")',
+    ], ids=["getfuncargvalue", "cached_setup"])
+    def test_scope_mismatch(self, testdir, method):
+        testdir.makeconftest("""
+            import pytest
+            finalized = []
+            created = []
+            @pytest.mark.funcarg(scope="function")
+            def pytest_funcarg__arg(request):
+                pass
+        """)
+        testdir.makepyfile(
+            test_mod1="""
+                import pytest
+                @pytest.mark.funcarg(scope="session")
+                def pytest_funcarg__arg(request):
+                    %s
+                def test_1(arg):
+                    pass
+            """ % method)
+        result = testdir.runpytest()
+        assert result.ret != 0
+        result.stdout.fnmatch_lines([
+            "*ScopeMismatch*You tried*function*from*session*",
+        ])
+