add test option to check if variables in template tags are defined

conftest.py

@@ -4,12 +4,15 @@
 
 from oioioi.base.tests import pytest_plugin as base_plugin
 from oioioi.contests.tests import pytest_plugin as contests_plugin
+from django.conf import settings
 
 
 def pytest_addoption(parser):
     parser.addoption(
         '--runslow', action='store_true', default=False, help="run slow tests"
     )
+    parser.addoption(
+        '--strict-template-vars', action='store_true', help="Raise errors for undefined template variables")
 
 
 # called for running each test
@@ -18,6 +21,12 @@ def pytest_runtest_setup(item):
     base_plugin.pytest_runtest_setup(item)
 
 
+def pytest_configure(config):
+    if config.getoption("--strict-template-vars"):
+        # this will raise an error if a template variable is not defined
+        settings.TEMPLATES[0]['OPTIONS']['string_if_invalid'] = '{% templatetag openvariable %} INVALID_VAR: %s {% templatetag closevariable %}'
+
+
 def pytest_collection_modifyitems(config, items):
     # --runslow flag: do not skip slow tests
     if config.getoption('--runslow', False):