def test_gold_prices_full_data_set():
actual = years_gold_value_decreased()
expected = (2013, 2009)
assert actual == expected
def test_gold_prices_1950_1999():
data = '\n'.join(gold_prices.strip().splitlines()[:10])
actual = years_gold_value_decreased(data)
expected = (1981, 1979)
assert actual == expected
def test_gold_prices_till_1980_1989():
data = '\n'.join(gold_prices.strip().splitlines()[-8:-6])
actual = years_gold_value_decreased(data)
expected = (1981, 1987)
assert actual == expected