@Test
public void top_level() {

	// given
	String levelName = "";
	// when
	Level level = transform(codemap, levelName);
	log.info("produced level '{}':\n{}", levelName, level.formatted());
	// then
	Component animal = new Component("animal");
	Component ghost = new Component("ghost");
	Component plant = new Component("plant");
	assertThat(level.name).isEqualTo(levelName);
	assertThat(level.components).containsExactly(animal, ghost, plant);
	assertThat(level.dependencies).containsExactly(
			new ComponentDep(animal, plant),
			new ComponentDep(plant, animal)
	);
	assertThat(level.dependency(animal, plant).strength).isEqualTo(2);
	assertThat(level.dependency(plant, animal).strength).isEqualTo(1);
	assertThat(level.component("animal").size).isGreaterThan(level.component("plant").size);
}