'Ensures template.html is available'

def test_exercise_code_path(self):

    def foo(n, a):
        s = a
        for i in range(n):
            s += i
        return s
    cres = compile_isolated(foo, [types.int32, types.int32])
    ta = cres.type_annotation
    buf = StringIO()
    ta.html_annotate(buf)
    output = buf.getvalue()
    buf.close()
    self.assertIn('foo', output)
