@Test
public void cannotDecelerateBeyondMinSpeed() {
Car car1 = new Car("Red", 100);
car1.decelerate(-1);
assertThat(car1.getSpeed(), is(0));
}
@Test
public void canDecelerate() {
Car car1 = new Car("Red", 100);
car1.decelerate(10);
assertThat(car1.getSpeed(), is(0));
}