Ensure render_to_string leaves the context instance stack in the state it was originally passed in.

        t = select_template(template_name)

    else:

        t = get_template(template_name)

    if context_instance:

    if not context_instance:

        return t.render(Context(dictionary))

    # Add the dictionary to the context stack, ensuring it gets removed again

    # to keep the context_instance in the same state it started in.

    context_instance.update(dictionary)

    else:

        context_instance = Context(dictionary)

    try:

        return t.render(context_instance)

    finally:

        context_instance.pop()

def select_template(template_name_list):

    "Given a list of template names, returns the first that can be loaded."

        # The two templates should not have the same content

        self.assertNotEqual(t1.render(Context({})), t2.render(Context({})))

class RenderToStringTest(unittest.TestCase):

    def setUp(self):

        self._old_TEMPLATE_DIRS = settings.TEMPLATE_DIRS

        settings.TEMPLATE_DIRS = (

            os.path.join(os.path.dirname(__file__), 'templates'),

        )

    def tearDown(self):

        settings.TEMPLATE_DIRS = self._old_TEMPLATE_DIRS

    def test_basic(self):

        self.assertEqual(loader.render_to_string('test_context.html'), 'obj:')

    def test_basic_context(self):

        self.assertEqual(loader.render_to_string('test_context.html',

                                                 {'obj': 'test'}), 'obj:test')

    def test_existing_context_kept_clean(self):

        context = Context({'obj': 'before'})

        output = loader.render_to_string('test_context.html', {'obj': 'after'},

                                         context_instance=context)

        self.assertEqual(output, 'obj:after')

        self.assertEqual(context['obj'], 'before')

if __name__ == "__main__":

    unittest.main()

obj:{{ obj }}

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