add unit test and change field name

src/python/pants/backend/native/register.py

@@ -11,7 +11,7 @@
 from pants.util.osutil import get_normalized_os_name
 
 
-class Platform(datatype('Platform', ['normed_os_name'])):
+class Platform(datatype('Platform', ['normalized_os_name'])):
 
   def __new__(cls):
     return super(Platform, cls).__new__(cls, get_normalized_os_name())

src/python/pants/backend/python/tasks/setup_py.py

@@ -92,7 +92,7 @@ def as_env_dict(self):
 
 @rule(SetupPyInvocationEnvironment, [Select(Platform), Select(NativeToolchain)])
 def get_setup_py_env(platform, native_toolchain):
-  is_linux = platform.normed_os_name == 'linux'
+  is_linux = platform.normalized_os_name == 'linux'
   joined_path = get_joined_path(
     native_toolchain.path_entries(), os.environ.copy(), prepend=is_linux)
   return SetupPyInvocationEnvironment(joined_path)

tests/python/pants_test/init/BUILD

@@ -10,13 +10,16 @@ python_tests(
     '3rdparty/python:setuptools',
     'src/python/pants/base:exceptions',
     'src/python/pants/build_graph',
+    'src/python/pants/engine:rules',
+    'src/python/pants/engine:selectors',
     'src/python/pants/goal',
     'src/python/pants/goal:task_registrar',
     'src/python/pants/init',
     'src/python/pants/option',
     'src/python/pants/subsystem',
     'src/python/pants/util:contextutil',
     'src/python/pants/util:dirutil',
+    'src/python/pants/util:objects',
     'tests/python/pants_test:base_test',
     'tests/python/pants_test/subsystem:subsystem_utils'
   ],

tests/python/pants_test/init/test_extension_loader.py

@@ -18,12 +18,15 @@
 from pants.build_graph.build_configuration import BuildConfiguration
 from pants.build_graph.build_file_aliases import BuildFileAliases
 from pants.build_graph.target import Target
+from pants.engine.rules import RootRule, rule
+from pants.engine.selectors import Select
 from pants.goal.goal import Goal
 from pants.goal.task_registrar import TaskRegistrar
 from pants.init.extension_loader import (PluginLoadOrderError, PluginNotFound, load_backend,
                                          load_backends_and_plugins, load_plugins)
 from pants.subsystem.subsystem import Subsystem
 from pants.task.task import Task
+from pants.util.objects import datatype
 
 
 class MockMetadata(EmptyProvider):
@@ -80,6 +83,19 @@ class DummyTask(Task):
   def execute(self): return 42
 
 
+class RootType(datatype('RootType', ['value'])):
+  pass
+
+
+class WrapperType(datatype('WrapperType', ['value'])):
+  pass
+
+
+@rule(WrapperType, [Select(RootType)])
+def example_rule(root_type):
+  yield WrapperType(root_type.value)
+
+
 class LoaderTest(unittest.TestCase):
 
   def setUp(self):
@@ -93,7 +109,7 @@ def tearDown(self):
 
   @contextmanager
   def create_register(self, build_file_aliases=None, register_goals=None, global_subsystems=None,
-                      module_name='register'):
+                      rules=None, module_name='register'):
 
     package_name = b'__test_package_{0}'.format(uuid.uuid4().hex)
     self.assertFalse(package_name in sys.modules)
@@ -113,6 +129,7 @@ def register_entrypoint(function_name, function):
       register_entrypoint('build_file_aliases', build_file_aliases)
       register_entrypoint('global_subsystems', global_subsystems)
       register_entrypoint('register_goals', register_goals)
+      register_entrypoint('rules', rules)
 
       yield package_name
     finally:
@@ -125,6 +142,7 @@ def assert_empty_aliases(self):
     self.assertEqual(0, len(registered_aliases.objects))
     self.assertEqual(0, len(registered_aliases.context_aware_object_factories))
     self.assertEqual(self.build_configuration.subsystems(), set())
+    self.assertEqual(0, len(self.build_configuration.rules()))
 
   def test_load_valid_empty(self):
     with self.create_register() as backend_package:
@@ -292,6 +310,14 @@ def global_subsystems():
       self.assertEqual(self.build_configuration.subsystems(),
                        {DummySubsystem1, DummySubsystem2})
 
+  def test_rules(self):
+    def rules():
+      return [example_rule, RootRule(RootType)]
+    with self.create_register(rules=rules) as backend_package:
+      load_backend(self.build_configuration, backend_package)
+      self.assertEqual(self.build_configuration.rules(),
+                       [example_rule, RootRule(RootType)])
+
   def test_backend_plugin_ordering(self):
     def reg_alias():
       return BuildFileAliases(targets={'override-alias': DummyTarget2})