Add name parameter to PluginManager.load_setuptools_entrypoints

Related to pytest-dev/pytest#4727

changelog/189.feature.rst

@@ -0,0 +1,5 @@
+``PluginManager.load_setuptools_entrypoints`` now accepts a ``name`` parameter that when given will
+load only entry points with that name.
+
+``PluginManager.load_setuptools_entrypoints`` also now returns the number of plugins loaded by the
+call, as opposed to the number of all plugins loaded by all calls to this method.

pluggy/manager.py

@@ -251,16 +251,22 @@ def check_pending(self):
                                 % (name, hookimpl.plugin),
                             )
 
-    def load_setuptools_entrypoints(self, entrypoint_name):
-        """ Load modules from querying the specified setuptools entrypoint name.
-        Return the number of loaded plugins. """
+    def load_setuptools_entrypoints(self, group, name=None):
+        """ Load modules from querying the specified setuptools ``group``.
+
+        :param str group: entry point group to load plugins
+        :param str name: if given, loads only plugins with the given ``name``.
+        :rtype: int
+        :return: return the number of loaded plugins by this call.
+        """
         from pkg_resources import (
             iter_entry_points,
             DistributionNotFound,
             VersionConflict,
         )
 
-        for ep in iter_entry_points(entrypoint_name):
+        count = 0
+        for ep in iter_entry_points(group, name=name):
             # is the plugin registered or blocked?
             if self.get_plugin(ep.name) or self.is_blocked(ep.name):
                 continue
@@ -275,7 +281,8 @@ def load_setuptools_entrypoints(self, entrypoint_name):
                 )
             self.register(plugin, name=ep.name)
             self._plugin_distinfo.append((plugin, ep.dist))
-        return len(self._plugin_distinfo)
+            count += 1
+        return count
 
     def list_plugin_distinfo(self):
         """ return list of distinfo/plugin tuples for all setuptools registered

testing/test_pluginmanager.py

@@ -449,8 +449,8 @@ def example_hook():
 def test_load_setuptools_instantiation(monkeypatch, pm):
     pkg_resources = pytest.importorskip("pkg_resources")
 
-    def my_iter(name):
-        assert name == "hello"
+    def my_iter(group, name=None):
+        assert group == "hello"
 
         class EntryPoint(object):
             name = "myname"
@@ -470,14 +470,16 @@ class PseudoPlugin(object):
     plugin = pm.get_plugin("myname")
     assert plugin.x == 42
     assert pm.list_plugin_distinfo() == [(plugin, None)]
+    num = pm.load_setuptools_entrypoints("hello")
+    assert num == 0  # no plugin loaded by this call
 
 
 def test_load_setuptools_version_conflict(monkeypatch, pm):
     """Check that we properly handle a VersionConflict problem when loading entry points"""
     pkg_resources = pytest.importorskip("pkg_resources")
 
-    def my_iter(name):
-        assert name == "hello"
+    def my_iter(group, name=None):
+        assert group == "hello"
 
         class EntryPoint(object):
             name = "myname"