def test_diff_none(self):
data = []
result = diff(data)
self.assertEqual(result, 0)
def test_diff_largenums(self):
data = [-7529383821,4738494329]
result = diff(data)
self.assertEqual(result, 2790889492)
def test_diff_value_missing(self):
data = [3]
result = diff(data)
self.assertEqual(result, -3)
def test_diff_zero(self):
data = [0,4]
result = diff(data)
self.assertEqual(result, -4)
def test_diff_pos_neg(self):
data = [-3,4]
result = diff(data)
self.assertEqual(result, -1)
def test_diff_neg(self):
data = [3,-4]
result = diff(data)
self.assertEqual(result, 1)
def test_diff_pos(self):
data = [-13,4]
result = diff(data)
self.assertEqual(result, 9)