def testPreexistingLetters(self): tiles = [None, None, None, 'x', 'z', 's', None, 'f', None] nodes = self.create_vertical_nodes(tiles) placements = Placement.placements('safe', nodes[5]) self.assertEqual(len(placements), 2) placement = placements[1] self.assertTrue(placement, Collision.safe(placement)) # The preexisting letters should contain the lettera 's' and 'f' because # when placing the word 'safe' across from the letter 's' the letter 'f' # would be used as well. letters = Collision.preexisting_letters(placement) self.assertEqual(len(letters), 2) self.assertEqual(letters[0], 's') self.assertEqual(letters[1], 'f')