Fails or pass depending on capture mode!

[olivierverdier]

I have a test which involves calling an external function (compiled from swig).
The test looks like

def test():
    data = preparedata()
    call_my_external_function(data)
    assert False

The problems is that pytest --capture=X fails or passes depending on X.

• fd : passes
• no: fails
• sys: fails

I expected a failure in all cases.

Version of pytest: 3.2.5, on Ubuntu.

I can't provide you with a minimal working example, because the key problem is the call to this function. If I place assert False before the call, then pytest fails no matter what the capturing metho is. So something happens when calling this exterior function.

How can I go ahead and debug this further?

[olivierverdier]

My mistake, I got confused by the output.