def test_shadows_can_overlap(self):
"""A Shadow X overlaps with Shadow Y if:
- X ends after Y starts AND Y starts before X ends
"""
first = Shadow(0, 0.4)
second = Shadow(0.4, 0.8)
third = Shadow(0.81, 0.95)
self.assertTrue(first.adjacent(second))
self.assertTrue(second.adjacent(first))
self.assertFalse(second.adjacent(third))
def test_shadows_do_not_always_overlap(self):
""" Distinct Shadows should not overlap."""
first = Shadow(0, 0.1)
second = Shadow(0.3, 0.4)
self.assertFalse(first.adjacent(second))
