...F
======================================================================
FAIL: this test is executed and fails, just as expected
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/shoshanaberleant/anaconda3/lib/python3.4/site-packages/nose/case.py", line 198, in runTest
    self.test(*self.arg)
  File "/Users/shoshanaberleant/anaconda3/lib/python3.4/site-packages/mock/mock.py", line 1305, in patched
    return func(*args, **keywargs)
  File "/Users/shoshanaberleant/silentfail.py", line 29, in test_nongenerator_should_fail
    assert_true(False)
AssertionError: False is not true

----------------------------------------------------------------------
Ran 4 tests in 0.004s

FAILED (failures=1)