[Pytest-commit] Issue #547: ``capsys``: ``AttributeError`` is raised and output is not captured when using the ``-s`` option (hpk42/pytest)

[Ignacy Sokołowski]

New issue 547: ``capsys``: ``AttributeError`` is raised and output is not captured when using the ``-s`` option
https://bitbucket.org/hpk42/pytest/issue/547/capsys-attributeerror-is-raised-and-output

Ignacy Sokołowski:

Test:

```
#!python

def print_foo():
    print('foo')

def test_print_foo(capsys):
    print_foo()
    output, __ = capsys.readouterr()
    assert output == 'foo\n'

```

Output for ``py.test``:

```
test_capsys.py .
```

Output for ``py.test -s``

```
test_capsys.py foo
F

================================= FAILURES ==================================
______________________________ test_print_foo _______________________________

capsys = <_pytest.capture.CaptureFixture object at 0x7fdf0ed8d9b0>

    def test_print_foo(capsys):
        print_foo()
>       output, __ = capsys.readouterr()

test_capsys.py:9: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = <_pytest.capture.CaptureFixture object at 0x7fdf0ed8d9b0>

    def readouterr(self):
        try:
            return self._capture.readouterr()
        except AttributeError:
>           return self._outerr
E           AttributeError: 'CaptureFixture' object has no attribute '_outerr'

../env/lib/python3.4/site-packages/_pytest/capture.py:205: AttributeError
```

Looks like the ``CaptureFixture._start`` method, where the ``_capture`` attribute is set, is not called.


This test fails on pytest 2.6 but passes on 2.5.2. On 2.5.2 the print output is captured even though the ``-s`` option was set. I think it's the expected behavior.