Switching from nose to unittest2 - how to continue after an error?
Terry Reedy
tjreedy at udel.edu
Mon Aug 25 17:47:40 EDT 2014
On 8/25/2014 2:13 PM, Skip Montanaro wrote:
> It appears that unittest in Python 2.7 should be capable enough that I
> can abandon nose in favor of python -m unittest. How do I get it to
> continue past the first failure?
Unittest normally stops with the first failure in a test_function. If
the asserts within a function are dependent (or normally passing), that
may be what you want.
I know of two ways to collect multiple failures within a test function:
1. Do it yourself. For instance, let iopairs be an iterable of input,
expected-output pairs for a function f.
def test_f(self):
failures = []
for inp, expect in iopairs:
actual = f(inp)
if actual != expect:
failures.append((inp, expect, actual))
assertFalse(failures, 'inp, expect, actual triples'
2. Use subtests, new in 3.4, and I suspect backported in unittest2 on
PyPI. This can be combined with the 1. above. Suppose two functions
should both pass the test above.
def test_g_h(self):
for f in (g, h):
with self.subTest(f=f):
<body of test_f>
As for asserts (from next message): self.assertTrue is equivalent to
assert, except it does not disappear with a compile flag. The other
assertX methods resolve to assertTrue, but for some, such as assert
raises, the equivalent in non-trivial. Even when the equivalent is
trivial, the specific methods usually gives better diagnostic messages.
This is especially true when comparing two non-empty collection for
equality. Knowing what is a one but the the other is very helpful.
--
Terry Jan Reedy
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