def test_init_matrix(self):
     '''
     Tests the init_matrix method of the Calculator class.
     '''
     matrix = Calculator.init_matrix(3, 1)
     self.assertEqual(1, matrix[0][0])
     self.assertEqual(1, matrix[0][1])
     self.assertEqual(1, matrix[0][2])
     self.assertEqual(1, matrix[1][0])
     self.assertEqual(1, matrix[1][1])
     self.assertEqual(1, matrix[1][2])
     self.assertEqual(1, matrix[2][0])
     self.assertEqual(1, matrix[2][1])
     self.assertEqual(1, matrix[2][2])