Fix error while issuing DeprecationWarning for __multicall__ usage

pluggy/__init__.py

@@ -657,7 +657,7 @@ def _add_hookimpl(self, hookimpl):
             warnings.warn(
                 "Support for __multicall__ is now deprecated and will be"
                 "removed in an upcoming release.",
-                warnings.DeprecationWarning
+                DeprecationWarning
             )
             self.multicall = _LegacyMultiCall
 

testing/test_pluginmanager.py

@@ -337,6 +337,17 @@ class PluginNo(object):
     assert l == [10]
 
 
+def test_multicall_deprecated(pm):
+    class P1(object):
+        @hookimpl
+        def m(self, __multicall__, x):
+            assert len(__multicall__.results) == 1
+            assert not __multicall__.hook_impls
+            return 17
+
+    pytest.deprecated_call(pm.register, P1())
+
+
 def test_add_hookspecs_nohooks(pm):
     with pytest.raises(ValueError):
         pm.add_hookspecs(10)