Fixed tests are written incorrectly: user function should be called per test block, and not in batch in advance, because user logs will cluster together before any test blocks, which cannot be correlated to the specific test assertion (and is pretty unreadable too).

Also, tests are not displaying expected value (0 is not the expected balance.), which is unacceptable.

ALSO, failure assertion message for the random tests is wrong: every one of them displays Transactions: [('2015-01-01 10:12:13', 123.45), ('2015-01-01 15:12:13', 123.45), ('2015-02-07 18:00:00', 123.45)] but this is the first fixed test, not the actual transactions being tested.