ext: Add ext.load_extensions tests and basic error handling

mopidy/ext.py

@@ -148,8 +148,21 @@ def load_extensions():
     for entry_point in pkg_resources.iter_entry_points('mopidy.ext'):
         logger.debug('Loading entry point: %s', entry_point)
         extension_class = entry_point.load(require=False)
-        extension = extension_class()
+
+        try:
+            if not issubclass(extension_class, Extension):
+                continue  # TODO: log this
+        except TypeError:
+            continue  # TODO: log that extension_class is not a class
+
+        try:
+            extension = extension_class()
+        except Exception:
+            continue  # TODO: log this
+
         extension.entry_point = entry_point
+
+        # TODO: store: (instance, entry_point, command, schema, defaults)
         installed_extensions.append(extension)
         logger.debug(
             'Loaded extension: %s %s', extension.dist_name, extension.version)

tests/test_ext.py

@@ -1,10 +1,14 @@
 from __future__ import absolute_import, unicode_literals
 
+import mock
+
 import pytest
 
 from mopidy import config, ext
 
 
+# ext.Extension
+
 @pytest.fixture
 def extension():
     return ext.Extension()
@@ -39,3 +43,76 @@ def test_validate_environment_does_nothing_by_default(extension):
 def test_setup_raises_not_implemented(extension):
     with pytest.raises(NotImplementedError):
         extension.setup(None)
+
+
+# ext.load_extensions
+
+class TestExtension(ext.Extension):
+    dist_name = 'Mopidy-Foobar'
+    ext_name = 'foobar'
+    version = '1.2.3'
+
+
+@mock.patch('pkg_resources.iter_entry_points')
+def test_load_extensions_no_extenions(mock_entry_points):
+    mock_entry_points.return_value = []
+    assert [] == ext.load_extensions()
+
+
+@mock.patch('pkg_resources.iter_entry_points')
+def test_load_extensions(mock_entry_points):
+    mock_entry_point = mock.Mock()
+    mock_entry_point.load.return_value = TestExtension
+
+    mock_entry_points.return_value = [mock_entry_point]
+
+    extensions = ext.load_extensions()
+    assert len(extensions) == 1
+    assert isinstance(extensions[0], TestExtension)
+
+
+@mock.patch('pkg_resources.iter_entry_points')
+def test_load_extensions_gets_wrong_class(mock_entry_points):
+
+    class WrongClass(object):
+        pass
+
+    mock_entry_point = mock.Mock()
+    mock_entry_point.load.return_value = WrongClass
+
+    mock_entry_points.return_value = [mock_entry_point]
+
+    assert [] == ext.load_extensions()
+
+
+@mock.patch('pkg_resources.iter_entry_points')
+def test_load_extensions_gets_instance(mock_entry_points):
+    mock_entry_point = mock.Mock()
+    mock_entry_point.load.return_value = TestExtension()
+
+    mock_entry_points.return_value = [mock_entry_point]
+
+    assert [] == ext.load_extensions()
+
+
+@mock.patch('pkg_resources.iter_entry_points')
+def test_load_extensions_creating_instance_fails(mock_entry_points):
+    mock_extension = mock.Mock(spec=ext.Extension)
+    mock_extension.side_effect = Exception
+
+    mock_entry_point = mock.Mock()
+    mock_entry_point.load.return_value = mock_extension
+
+    mock_entry_points.return_value = [mock_entry_point]
+    assert [] == ext.load_extensions()
+
+
+@mock.patch('pkg_resources.iter_entry_points')
+def test_load_extensions_store_entry_point(mock_entry_points):
+    mock_entry_point = mock.Mock()
+    mock_entry_point.load.return_value = TestExtension
+    mock_entry_points.return_value = [mock_entry_point]
+
+    extensions = ext.load_extensions()
+    assert len(extensions) == 1
+    assert extensions[0].entry_point == mock_entry_point