public void Planet_Moons_ReturnsNonEmpty(int planetId)
{
var planet = Planets.Get(planetId).Value;
var moons = planet.Moons().ToList();
moons.Should().NotHaveCount(0);
}
public void Planet_AsteroidBelts_ReturnsNonEmpty(int planetId)
{
var planet = Planets.Get(planetId).Value;
var belts = planet.AsteroidBelts().ToList();
belts.Should().NotHaveCount(0);
}