def test_stock_price_earnings_ratio(self):
"""
Tests correct price-earnings calculation for both `common` and
`preferred` stock types.
"""
# Make a mock object for testing.
sALE = Stock('ALE', 'common', 23, nan, 60)
# Add some mock Trades.
sALE.buy(500, 25)
sALE.sell(300, 15)
self.assertEqual(len(sALE._trades), 2)
# Make a mock object for testing.
sGIN = Stock('GIN', 'preferred', 8, 0.02, 100)
# Add some mock Trades.
sGIN.buy(320, 95)
sGIN.sell(180, 110)
self.assertEqual(len(sGIN._trades), 2)
# `ALE` stock should use the last_dividend as dividend
self.assertEqual(sALE.price_earnings_ratio(),
((500*25+300*15)/(500+300)) / 23.)
# But `GIN` stock should the fixed_dividend * par_value as dividend
self.assertEqual(sGIN.price_earnings_ratio(),
((320*95+180*110)/(320+180)) / (0.02 * 100))
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_price_no_recent(self):
"""
Tests stock (ticker) price calculation for the case with no recent
trades.
"""
# Make a mock object for testing.
sALE = Stock('ALE', 'common', 23, nan, 60)
# A stock without trades has a ticker price equal to its par value.
self.assertEqual(sALE.stock_price(), 60)
# Add some mock Trades between -30 and -15 minutes relative to now.
sALE.buy(500, 25,
datetime.datetime.now() - datetime.timedelta(minutes=16))
sALE.sell(300, 15,
datetime.datetime.now() - datetime.timedelta(minutes=22))
self.assertEqual(len(sALE._trades), 2)
# Now add some mock Trades prior to 30 minutes in the past.
sALE.buy(250, 33,
datetime.datetime.now() - datetime.timedelta(minutes=35))
sALE.sell(125, 55,
datetime.datetime.now() - datetime.timedelta(minutes=39))
self.assertEqual(len(sALE._trades), 4)
# Since the latest trade happened at -16 minutes relative to now, the
# time window in which to calculate the stock price is [-29, -14].
self.assertEqual(sALE.stock_price(),
((500*25 + 300*15) / (500+300)))
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)))
def test_stock_price(self):
"""
Tests stock (ticker) price calculation.
"""
# Make a mock object for testing.
sALE = Stock('ALE', 'common', 23, nan, 60)
# A stock without trades has a ticker price equal to its par value.
self.assertEqual(sALE.stock_price(), 60)
# Add some mock Trades.
sALE.buy(500, 25)
sALE.sell(300, 15)
self.assertEqual(len(sALE._trades), 2)
# Easy case for ticker price with two Trades.
self.assertEqual(sALE.stock_price(), ((500*25)+(300*15))/(500+300))
# Add some mock Trades in the distant past (such that they are excluded
# from the average).
sALE.buy(100, 87, datetime.datetime.now() -
datetime.timedelta(minutes=16))
sALE.buy(23, 34, datetime.datetime.now() -
datetime.timedelta(minutes=15))
self.assertEqual(len(sALE._trades), 4)
# Stock price should be unchanged.
self.assertEqual(sALE.stock_price(), ((500*25)+(300*15))/(500+300))
def test_stock_buy_sell(self):
"""
Test buying and selling stocks.
"""
# Make a mock object for testing.
# NOTE there are better ways to do this!
sALE = Stock('ALE', 'common', 23, nan, 60)
# Trade price should not be a string.
with self.assertRaises(AssertionError):
sALE.buy(500, 55, '2017 06 05 13 42 00')
# Trade price should not be negative.
with self.assertRaises(AssertionError):
sALE.buy(500, -23)
# Trade price should not be a float.
with self.assertRaises(AssertionError):
sALE.buy(500, 123.0)
# Trade price should not be a string.
with self.assertRaises(AssertionError):
sALE.sell(500, 55, '2017 06 05 13 42 00')
# Trade price should not be negative.
with self.assertRaises(AssertionError):
sALE.sell(500, -23)
# Trade price should not be a float.
with self.assertRaises(AssertionError):
sALE.sell(500, 123.0)
# `Buy` records should have a `+1` number in the buy_sell tuple record.
sALE.buy(500, 25)
self.assertEqual(sALE._trades[-1].buy_sell, 1)
# `Sell` records should have a `-1` number in the buy_sell tuple record.
sALE.sell(300, 15)
self.assertEqual(sALE._trades[-1].buy_sell, -1)
# Trading cannot happen in the future.
with self.assertRaises(AssertionError):
sALE.buy(500, 25,
datetime.datetime.now() + datetime.timedelta(minutes=1))
