explorer selftests should make pyqt4 a soft dependency

[Martin Pool]

If the explorer plugin is present but pyqt4 is not installed, you can't run the bzr test suite at all, because explorer has an unguarded import statement. I think there is a mechanism by which it can turn this into just skipping the tests?

2.694 Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 842, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 1037, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 654, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.6/dist-packages/bzrlib/builtins.py", line 3489, in run
    result = selftest(**selftest_kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/tests/__init__.py", line 3243, in selftest
    suite = test_suite(keep_only, starting_with)
  File "/usr/lib/python2.6/dist-packages/bzrlib/tests/__init__.py", line 3688, in test_suite
    plugin_suite = plugin.load_plugin_tests(loader)
  File "/usr/lib/python2.6/dist-packages/bzrlib/plugin.py", line 383, in load_plugin_tests
    return loader.loadTestsFromModule(self.module)
  File "/usr/lib/python2.6/dist-packages/bzrlib/tests/TestUtil.py", line 129, in loadTestsFromModule
    return load_tests(basic_tests, module, self)
  File "/home/mbp/.bazaar/plugins/explorer/__init__.py", line 43, in load_tests
    return load_tests(basic_tests, module, loader)
  File "/home/mbp/.bazaar/plugins/explorer/tests/__init__.py", line 86, in load_tests
    suite.addTests(loader.loadTestsFromModuleNames(mod_names))
  File "/usr/lib/python2.6/dist-packages/bzrlib/tests/TestUtil.py", line 92, in loadTestsFromModuleNames
    result.addTests(self.loadTestsFromModuleName(name))
  File "/usr/lib/python2.6/dist-packages/bzrlib/tests/TestUtil.py", line 97, in loadTestsFromModuleName
    module = _load_module_by_name(name)
  File "/usr/lib/python2.6/dist-packages/bzrlib/tests/TestUtil.py", line 166, in _load_module_by_name
    module = __import__(mod_name)
  File "/home/mbp/.bazaar/plugins/explorer/tests/test_test_suite.py", line 19, in <module>
    from PyQt4 import QtCore, QtGui
ImportError: No module named PyQt4

[Alexander Belchenko (bialix)]

We have similar guard code in qbzr for the same reasons. Just need to copy-paste the approach, perhaps.

[Ian Clatworthy (ian-clatworthy)]

John,

Could you take a look at this please?

[Alexander Belchenko (bialix)]

To be honest bzr-svn is also has similar problem: it blocks running selftest if there is no subvertpy library installed:

C:\work\Bazaar\bzr-2a\bzr.dev>py26 bzr selftest --list-only > NUL
bzr: ERROR: No module named subvertpy
You may need to install this Python library separately.
bzr: warning: some compiled extensions could not be loaded; see <https://answers.launchpad.net/bzr/+faq/703>

Why Explorer is any worse then?