version 2.0.0 breaks pyqt4 api v2

[montefra]

Running tests via tox with pytest-qt==2.0.0 with pyqt4 and api v2 gives me:

py27 runtests: commands[1] | py.test
INTERNALERROR> Traceback (most recent call last):
INTERNALERROR> File "/.../.tox/py27/local/lib/python2.7/site-packages/_pytest/main.py", line 90, in wrap_session
INTERNALERROR> config._do_configure()
INTERNALERROR> File "/.../.tox/py27/local/lib/python2.7/site-packages/_pytest/config.py", line 839, in _do_configure
INTERNALERROR> self.hook.pytest_configure.call_historic(kwargs=dict(config=self))
INTERNALERROR> File "/.../.tox/py27/local/lib/python2.7/site-packages/_pytest/vendored_packages/pluggy.py", line 729, in call_historic
INTERNALERROR> self._hookexec(self, self._nonwrappers + self._wrappers, kwargs)
INTERNALERROR> File "/.../.tox/py27/local/lib/python2.7/site-packages/_pytest/vendored_packages/pluggy.py", line 338, in _hookexec
INTERNALERROR> return self._inner_hookexec(hook, methods, kwargs)
INTERNALERROR> File "/.../.tox/py27/local/lib/python2.7/site-packages/_pytest/vendored_packages/pluggy.py", line 333, in
INTERNALERROR> _MultiCall(methods, kwargs, hook.spec_opts).execute()
INTERNALERROR> File "/.../.tox/py27/local/lib/python2.7/site-packages/_pytest/vendored_packages/pluggy.py", line 596, in execute
INTERNALERROR> res = hook_impl.function(*args)
INTERNALERROR> File "/.../.tox/py27/local/lib/python2.7/site-packages/pytestqt/plugin.py", line 167, in pytest_configure
INTERNALERROR> qt_api.set_qt_api(config.getini('qt_api'))
INTERNALERROR> File "/.../.tox/py27/local/lib/python2.7/site-packages/pytestqt/qt_compat.py", line 74, in set_qt_api
INTERNALERROR> sip.setapi("QDate", 2)
INTERNALERROR> ValueError: API 'QDate' has already been set to version 1
ERROR: InvocationError: '/.../.tox/py27/bin/py.test'

Version 1.11.0 runs correctly.

According to git bisects the offending commit is:

commit aaada5b
Author: Bruno Oliveira nicoddemus@gmail.com
Date: Thu May 12 20:19:54 2016 -0300

Qt API lazy load in qt_compat and qt_api config option

Fix #129

I think that the problem is that now PyQt4 is loaded before setting the API version. This is a problems only for PyQt4 under python2, but unfortunatly I have it's a combination I have to provide.

For the moment I'll fix the required version to pytest-qt to <= 1.11. If I have I'll try to figure out the issue.

[montefra]

Now I'm more puzzled than before:

	v 1.11	v2.0
.tox/py27/bin/py.test	OK	OK
tox -e py27, with py27: PYTEST_QT_API = pyqt4v2 in setenv	OK	FAIL
tox -e py27, without py27: PYTEST_QT_API = pyqt4v2 in setenv	OK	OK

If I remember correctly once I had to run py.test like PYTEST_QT_API = pyqt4v2 py.test to get it work. So I added it into tox.ini to avoid lots of typing.
But now is the other way around.

What happened with the new version?

[The-Compiler]

The new version uses PyQt5 instead of PyQt4 by default without PYTEST_QT_API FWIW.

[nicoddemus]

Hmmm that's really strange if you are setting PYTEST_QT_API. This is the relevant line from qt_compat.py:

    def set_qt_api(self, api):
        self.pytest_qt_api = api or self._get_qt_api_from_env() or self._guess_qt_api()

I'm guessing guess_qt_api could cause problems in this case because it tries to import PyQt4 eventually, which would explain your error, but if you are setting PYTEST_QT_API, then self._guess_qt_api should never be called.

Could you try setting qt_api=pyqt4v2 in your pytest.ini file to see what you get?

[nicoddemus]

Oh this just occurred to me: before 2.0 pytest-qt would load PyQt bindings during import time, so it might be the case that before it would set the API version to v2 before importing PYQt4. In version 2 though importing PyQt4 is delayed until pytest_configure executes, so perhaps what might be happening is that some other code is importing PyQt4 (perhaps a conftest.py file for example).

[montefra]

As usual, when it gets late, mistakes happen. That's the correct matrix

	v 1.11	v2.0
.tox/py27/bin/py.test	FAIL	OK
PYTEST_QT_API=pyqt4v2 .tox/py27/bin/py.test	OK	FAIL
PYTEST_QT_API=pyqt4 .tox/py27/bin/py.test	FAIL	OK
.tox/py27/bin/py.test, with qt_api=pyqt4v2 in pytest.ini	FAIL	FAIL
tox -e py27, with py27: PYTEST_QT_API = pyqt4v2 in setenv	OK	FAIL
tox -e py27, without py27: PYTEST_QT_API = pyqt4v2 in setenv	FAIL	OK
tox -e py27, with py27: PYTEST_QT_API = pyqt4 in setenv	FAIL	OK

When it fails with v1.11 I get the following traceback:

Traceback (most recent call last):
File "/.../.tox/py27/local/lib/python2.7/site-packages/_pytest/config.py", line 320, in _importconftest
mod = conftestpath.pyimport()
File "/.../.tox/py27/local/lib/python2.7/site-packages/py/_path/local.py", line 650, in pyimport
import(modname)
File "/.../tests/conftest.py", line 12, in
sip.setapi('QString', 2) # for ginga compatibility
ValueError: API 'QString' has already been set to version 1
ERROR: could not load /.../tests/conftest.py

When it fails with v2 I get the one at the beginning of the issue.

In my conf test I do:

import sip                                                                                                                                                            
sip.setapi('QString', 2)  # for ginga compatibility
sip.setapi('QVariant', 2)

and then I import a bunch of modules that import PyQt4.

I don't set other things to API 2 because I don't need. In the light of @nicoddemus clarification, this explain why it complains about API 'QDate'.

If I don't set the qt_api it tries to guess it as following:

• PyQt5: fails because PyQt4 is already imported
• PySide: fails because I don't have it
• PyQt4: success!

If I had PySide I must set the qt_api=pyqt4.

Are all the test modules loaded before pytest-qt loads PyQt/PySide?

We probably should update the documentation with something like:

• qt_api=pyqt4v2 is useful and usable only if:
  • all PyQt4 and sip imports are done within functions/methods, i.e. are executed at run time
  • sip.setapi is used for all the types it's used by pytest-qt
• If PyQt4 is imported at the module level and the api is set in the package/conftest.py/test_*.py, use qt_api=pyqt4

Does it make sense?

[nicoddemus]

Thanks for the detailed followup!

Are all the test modules loaded before pytest-qt loads PyQt/PySide?

I think test modules will be imported only after conftest.py file has been imported, which is the root of your problem as far as I can tell: in 2.0 pytest-qt will only import qt modules during pytest_configure, which will be called only after your conftest.py was already imported and sip.setapi was called. In versions < 2.0, pytest-qt would import qt modules when the plugin was loaded, long before conftest.py files were imported.

We probably should update the documentation with something like:

I agree, pyqt4v2 is probably only useful if one wants to use all types in v2 (which I personally find a little odd to not be your case).

One minor correction: "all PyQt4 and sip imports are done within functions/methods, i.e. are executed at run time" is not true for test modules, only for conftest.py files: the pytest_configure hook will be called before any other test modules are imported, so it should be fine to make global PyQt4 imports for test modules .

[montefra]

Thank you again for the detailed information

I agree, pyqt4v2 is probably only useful if one wants to use all types in v2 (which I personally find a little odd to not be your case).

I never had problems using only two objects with the API v2. I'll investigate if this is indeed a problem.
Actually: the API is set in the conftest.py or in any of the packages imported there, pyqt4v2 is superfluous and (in cases like mine) leads to errors.

One minor correction: "all PyQt4 and sip imports are done within functions/methods, i.e. are executed at run time" is not true for test modules, only for conftest.py files: the pytest_configure hook will be called before any other test modules are imported, so it should be fine to make global PyQt4 imports for test modules .

Thanks for the correction.

I see if I find some time in the next days to do a PR to update the documentation with some of those information.

[nicoddemus]

I see if I find some time in the next days to do a PR to update the documentation with some of those information.

If you could, that would be great! 👍 😁