def test_stock_dividend_yield_preferred(self):
"""
Tests correct dividend yield calculation for `preferred` stock types.
"""
# Make a mock object for testing.
sGIN = Stock('GIN', 'preferred', 8, 0.02, 100)
# A stock without trades has a default ticker price equal to its par
# value. In this case, `preferred` stock types should have a price
# earnings ratio equal to their par value.
self.assertEqual(sGIN.dividend_yield(), 0.02)
# Add some mock Trades.
sGIN.buy(320, 95)
sGIN.sell(180, 110)
self.assertEqual(len(sGIN._trades), 2)
# `preferred` stocks should not use the `common` calculation for
# dividend yields...
self.assertNotEqual(sGIN.dividend_yield(),
8 / ((320*95 + 180*110) / (320+180)))
# ... instead, they should use the `preferred` calculation.
self.assertEqual(sGIN.dividend_yield(),
(0.02 * 100) / ((320*95 + 180*110) / (320+180)))
def test_stock_dividend_yield_common(self):
"""
Tests correct dividend yield calculation for `common` stock types.
"""
# Make a mock object for testing.
sALE = Stock('ALE', 'common', 23, nan, 60)
# A stock without trades has a default ticker price equal to its par
# value.
self.assertEqual(sALE.dividend_yield(), 23. / 60)
# Add some mock Trades.
sALE.buy(500, 25)
sALE.sell(300, 15)
self.assertEqual(len(sALE._trades), 2)
# The dividend yield calculation should now use a ticker price
# determined from the average trading price.
self.assertEqual(sALE.dividend_yield(), 23. /
(((500*25)+(300*15))/(500+300)))