              with self.assertRaises(TemplateSyntaxError):
                  Template('{% load i18n %}{% blocktrans context with month="May" %}{{ month }}{% endblocktrans %}')
              with self.assertRaises(TemplateSyntaxError):
                  Template('{% load i18n %}{% blocktrans context %}{% endblocktrans %}')
              with self.assertRaises(TemplateSyntaxError):
                  Template(
                      '{% load i18n %}{% blocktrans count number=2 context %}'
                      '{{ number }} super result{% plural %}{{ number }}'
                      ' super results{% endblocktrans %}'
                  )
 
</s> remove             with self.assertRaises(TemplateSyntaxError):
 </s> add             msg = '"context" in %r tag expected exactly one argument.' % 'blocktrans'
            with self.assertRaisesMessage(TemplateSyntaxError, msg): </s> remove             with self.assertRaises(TemplateSyntaxError):
 </s> add             msg = "Unknown argument for 'blocktrans' tag: %r."
            with self.assertRaisesMessage(TemplateSyntaxError, msg % 'month="May"'): </s> remove         with self.assertRaises(TemplateSyntaxError):
 </s> add         with self.assertRaisesMessage(TemplateSyntaxError, msg): </s> remove         with self.assertRaises(TemplateSyntaxError):
 </s> add         with self.assertRaisesMessage(TemplateSyntaxError, msg): </s> remove         with self.assertRaises(TemplateSyntaxError):
 </s> add         with self.assertRaisesMessage(TemplateSyntaxError, msg):
            with self.assertRaisesMessage(TemplateSyntaxError, msg):
              with self.assertRaises(TemplateSyntaxError):
                  Template('{% load i18n %}{% blocktrans context with month="May" %}{{ month }}{% endblocktrans %}')
              with self.assertRaises(TemplateSyntaxError):
                  Template('{% load i18n %}{% blocktrans context %}{% endblocktrans %}')
            with self.assertRaisesMessage(TemplateSyntaxError, msg):
                  Template(
                      '{% load i18n %}{% blocktrans count number=2 context %}'
                      '{{ number }} super result{% plural %}{{ number }}'
                      ' super results{% endblocktrans %}'
                  )
keep keep keep keep replace keep keep keep keep keep
 Used assertRaisesMessage() to test Django's error messages. 
tests/template_tests/syntax_tests/i18n/test_blocktrans.py