def test_str_representation_of_term_is_correct(self):
with self.subTest('Coefficient is bigger than 1'):
t = Term(coeff=2, variable='x', power=3)
expected = '2*x^3'
self.assertEqual(expected, str(t))
with self.subTest('Coefficient is 1'):
t = Term(coeff=1, variable='x', power=3)
expected = 'x^3'
self.assertEqual(expected, str(t))
with self.subTest('Power is 1'):
t = Term(coeff=1, variable='x', power=1)
expected = 'x'
self.assertEqual(expected, str(t))
with self.subTest('Coeff is bigger than 1, power is 1'):
t = Term(coeff=2, variable='x', power=1)
expected = '2*x'
self.assertEqual(expected, str(t))
with self.subTest('Term is constant'):
t = Term.constant(2)
expected = '2'
self.assertEqual(expected, str(t))
def test_is_constant(self):
with self.subTest('Term with coeff, variable and power is not'):
t = Term(coeff=2, variable='x', power=3)
self.assertFalse(t.is_constant)
with self.subTest('Constant term is constant'):
value = 2
t = Term.constant(value)
self.assertTrue(t.is_constant)
self.assertEqual(value, t.coeff)
self.assertIsNone(t.variable)
self.assertEqual(0, t.power)
def test_derivative(self):
with self.subTest('Derivative of constant is 0'):
t = Term.constant(2)
expected = Term.constant(0)
self.assertEqual(expected, t.derivative())
with self.subTest('Derivative of 2*x^1'):
t = Term(coeff=2, variable='x', power=1)
expected = Term.constant(2)
self.assertEqual(expected, t.derivative())
with self.subTest('Derivative of x^1'):
t = Term(coeff=1, variable='x', power=1)
expected = Term.constant(1)
self.assertEqual(expected, t.derivative())
with self.subTest('Derivative of 2*x^2'):
t = Term(coeff=2, variable='x', power=2)
expected = Term(coeff=4, variable='x', power=1)
self.assertEqual(expected, t.derivative())