add the file settings_dev.py to be cleaned, set cache timeout to 0 (i.e. disable cache for tests)
{% extends "site/layout/base.html" %}
{% load i18n %}
{% block content %}
<h1>404: {% blocktrans %}Page not found{% endblocktrans %}</h1>
{% blocktrans %}The requested page could not be found.{% endblocktrans %}
{% endblock %}