def test_merge_unique_in_a_first_level(tmpdir):
    """Assert merge unique in a first level."""
    settings_file_yaml = """
    default:
        colors: "@merge_unique green,blue"
        non_exist: "@merge_unique item1,item2"
    """
    tmpdir.join("settings.yaml").write(settings_file_yaml)
    settings = LazySettings(
        environments=True,
        settings_file="settings.yaml",
        COLORS=["red", "green"],
    )
    settings.reload()
    assert settings.COLORS == ["red", "green", "blue"]
    assert settings.NON_EXIST == ["item1", "item2"]
Assert merge unique in a first level.
tests/test_yaml_loader.py