public async Task Returns_503_When_IBannerRepository_Throws_Exception()
{
string id = "";
_bannerRepository.Setup(br => br.GetBannerHtml(id)).Throws(new Exception("DB down"));
var response = await _bannerController.GetBannerHtml(id);
Assert.IsTrue(response is StatusCodeResult);
var statusCode = (StatusCodeResult)response;
statusCode.StatusCode.Should().Be((int)HttpStatusCode.ServiceUnavailable);
}