Parallel test runner swallows standard output

[pzahemszky]

The parallel test runner seems to swallow the standard output. See the example below.

test_haas_parallel.py:

import unittest


class TestHaas(unittest.TestCase):

    def test_haas_one(self):
        print('one')

    def test_haas_two(self):
        print('two')

Running haas with the default test runner displays the one and two messages as expected:

$ haas test_haas_parallel.py
one
.two
.
----------------------------------------------------------------------
Ran 2 tests in 0.000s

OK

Running haas with the --runner parallel option makes them disappear.

$ haas --runner parallel test_haas_parallel.py
..
----------------------------------------------------------------------
Ran 2 tests in 0.121s

OK

---

Python 3.6.5
haas 0.8.0
stevedore 1.29.0

[itziakos]

After some investigation on the behaviour of the parallel runner, I found the following:

• The stdout and stderr is buffered independently for each test (https://github.com/scalative/haas/blob/master/haas/plugins/parallel_runner.py#L51)
• The stdout and stderr content is normally passed to the TestResult through the from_test_case contructor (https://github.com/scalative/haas/blob/master/haas/result.py#L249)
• The from_test_case will however ignore the stdout/stderr content if the test did not fail.

So the bug is that the stdout/stderr content is ignored instead of being collected by the parent process. I suspect that the solution to this bug is going to be a little more involved and probably require some small redesign