tests: introduce test_context to handle internationalization As preparation to the migration to Turbogears2, introduce a test_context context manager to wrap certain tests. The context manager provides a translator for tests that need it. This translator was previously provided globally to all tests via the TestController. When swapping Pylons with Turbogears2, the new file kallithea/tests/test_context.py can be removed, and the test_context from tg2/tg/util/webtest.py should be used.

[pytest]
# only look for tests in kallithea/tests
python_files = kallithea/tests/**/test_*.py
addopts =
    # --verbose
    # show extra test summary info as specified by chars (f)ailed, (E)error, (s)skipped, (x)failed, (X)passed, (w)warnings.
    -rfEsxXw
    # Shorter scrollbacks; less stuff to scroll through
    --tb=short