def test_replace_source_not_found():
source_a = DictConfigSource({})
source_b = DictConfigSource({})
config = Config()
config.add_source(source_a)
with pytest.raises(ValueError):
config.replace_source(source_b, source_a)
def test_add_source():
c = Config()
with pytest.raises(TypeError):
bad_type: ConfigSource = 3
c.add_source(bad_type)
assert len(c.config_sources) == 0
new_source = DictConfigSource({})
c.add_source(new_source)
assert len(c.config_sources) == 1
assert c.config_sources[-1] is new_source