def test_tall_rectangle(self):
     self.assertEqual([[None] * 4] * 5, wg.create_empty_grid(4, 5))
 def test_zero_dimensions(self):
     self.assertEqual([], wg.create_empty_grid(0, 0))
 def test_wide_rectangle(self):
     self.assertEqual([[None] * 5] * 4, wg.create_empty_grid(5, 4))
 def test_square(self):
     self.assertEqual([[None] * 4] * 4, wg.create_empty_grid(4, 4))
 def test_unit_dimensions(self):
     self.assertEqual([[None]], wg.create_empty_grid(1, 1))
 def test_zero_width(self):
     self.assertEqual([[] for _ in range(4)], wg.create_empty_grid(0, 4))
 def test_zero_height(self):
     self.assertEqual([], wg.create_empty_grid(4, 0))