def test_percentage_change_50pc(self):
"""Percentage change between values where one is 50% of the other"""
value_1 = 2000
value_2 = 4000
diff_1 = calc_percentage_change(value_2, value_1)
diff_2 = calc_percentage_change(value_1, value_2)
self.assertEquals(abs(diff_1), diff_2)
self.assertAlmostEquals(1, diff_2, 2)
def test_percentage_change(self):
"""Percentage change between two values that are almost equal"""
value_1 = 3999.9999999
value_2 = 4000
diff_1 = calc_percentage_change(value_2, value_1)
diff_2 = calc_percentage_change(value_1, value_2)
self.assertAlmostEquals(diff_1, diff_2)
self.assertAlmostEquals(0.00000, diff_1, 2)
def test_percentage_change_99pc(self):
"""Percentage change between a very small value and a relatively large
value"""
value_1 = 1
value_2 = (2**32) + 1
diff_1 = calc_percentage_change(value_2, value_1)
diff_2 = calc_percentage_change(value_1, value_2)
self.assertAlmostEquals(-0.999999, diff_1, 2)
self.assertAlmostEquals(2**32, diff_2, 2)
