simplify load_setuptools_entrypoints and refine comments/docstrings

--HG--
branch : more_plugin

_pytest/config.py

@@ -800,7 +800,10 @@ class Config(object):
             args[:] = self.getini("addopts") + args
         self._checkversion()
         self.pluginmanager.consider_preparse(args)
-        self.pluginmanager.load_setuptools_entrypoints("pytest11")
+        try:
+            self.pluginmanager.load_setuptools_entrypoints("pytest11")
+        except ImportError as e:
+            self.warn("I2", "could not load setuptools entry import: %s" % (e,))
         self.pluginmanager.consider_env()
         self.known_args_namespace = ns = self._parser.parse_known_args(args)
         try:

_pytest/core.py

@@ -256,10 +256,6 @@ class PluginManager(object):
             return hc
         return orig
 
-    def get_canonical_name(self, plugin):
-        """ Return canonical name for a plugin object. """
-        return getattr(plugin, "__name__", None) or str(id(plugin))
-
     def register(self, plugin, name=None):
         """ Register a plugin and return its canonical name or None if the name
         is blocked from registering.  Raise a ValueError if the plugin is already
@@ -344,6 +340,13 @@ class PluginManager(object):
         """ Return True if the plugin is already registered. """
         return plugin in self._plugin2hookcallers
 
+    def get_canonical_name(self, plugin):
+        """ Return canonical name for a plugin object. Note that a plugin
+        may be registered under a different name which was specified
+        by the caller of register(plugin, name). To obtain the name
+        of an registered plugin use ``get_name(plugin)`` instead."""
+        return getattr(plugin, "__name__", None) or str(id(plugin))
+
     def get_plugin(self, name):
         """ Return a plugin or None for the given name. """
         return self._name2plugin.get(name)
@@ -386,14 +389,11 @@ class PluginManager(object):
                                 "unknown hook %r in plugin %r" %(name, plugin))
 
     def load_setuptools_entrypoints(self, entrypoint_name):
-        """ Load modules from querying the specified entrypoint name.
-        Return None if setuptools was not operable, otherwise
-        the number of loaded plugins. """
-        try:
-            from pkg_resources import iter_entry_points, DistributionNotFound
-        except ImportError:
-            return # XXX issue a warning
+        """ Load modules from querying the specified setuptools entrypoint name.
+        Return the number of loaded plugins. """
+        from pkg_resources import iter_entry_points, DistributionNotFound
         for ep in iter_entry_points(entrypoint_name):
+            # is the plugin registered or blocked?
             if self.get_plugin(ep.name) or ep.name in self._name2plugin:
                 continue
             try:

testing/test_core.py

@@ -419,8 +419,8 @@ class TestAddMethodOrdering:
     def test_load_setuptools_not_installed(self, monkeypatch, pm):
         monkeypatch.setitem(py.std.sys.modules, 'pkg_resources',
             py.std.types.ModuleType("pkg_resources"))
-        assert pm.load_setuptools_entrypoints("qwe") is None
-        # ok, we did not explode
+        with pytest.raises(ImportError):
+            pm.load_setuptools_entrypoints("qwe")
 
 
 class TestPytestPluginInteractions: