'Fail silently when a variable is not found in the current context'

@setup({'basic-syntax04': 'as{{    missing    }}df'})
def test_basic_syntax04(self):

    output = self.engine.render_to_string('basic-syntax04')
    if self.engine.string_if_invalid:
        self.assertEqual(output, 'asINVALIDdf')
    else:
        self.assertEqual(output, 'asdf')
