I have a method:
def cargo_add(self, new_cargo):
assert (new_cargo.weight + self.cargo_weight()) \
<= self.cargocapacity, "Not enough Space left"
And i would like to test its functionallyty with someting like:
def _test_cargo_add():
assert cShip.cargo_add(c1) is AssertionError
So i can test the error Handling. But when the first assert is wrong the program stopps.
If your testing framework does not have helpers for that, or you are not using any, you can do this only using builtins by
using try .. except .. else and isinstance:
>>> def f(): # define a function which AssertionErrors.
... assert False
...
>>> f() # as expected, it does
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 2, in f
AssertionError
>>> try: # wrap it
... f()
... except Exception as e: # and assert it really does
... assert isinstance(e, AssertionError)
... else:
... raise AssertionError("There was'nt any Exception, but we expected an AssertionError!")
...
>>>
or just catch the AssertionError explicitly:
>>> try:
... f()
... except AssertionError:
... pass # all good, we got an AssertionError
... except Exception:
... raise AssertionError("There was an Exception, but it wasn't an AssertionError!")
... else:
... raise AssertionError("There was'nt any Exception, but we expected an AssertionError!")
...
If you are testing using unittest you can use assertRaises
with self.assertRaises(AssertionError):
cShip.cargo_add(c1)
