def test_require_one_convenience_raises_if_no_result():
c = Component()
c.require = Mock(return_value=[])
with pytest.raises(SilentConfigurationError):
c.require_one('asdf')
def test_require_one_convenience_raises_if_more_results():
c = Component()
c.require = Mock(return_value=[1, 2])
with pytest.raises(KeyError):
c.require_one('asdf')
def test_require_one_convenience_api_returns_scalar():
c = Component()
c.require = Mock(return_value=[1])
assert 1 == c.require_one('asdf')
