public async Task TestExpiringCredentials()
{
// test that non-expired credentials work
await TestExpireOffset(returnExpiredCredentials: false);
// test that expired credentials do not work
await TestExpireOffset(returnExpiredCredentials: true);
// test that various dates work
await TestExpire(DateTime.Now, expectFailure: true);
await TestExpire(DateTime.UtcNow, expectFailure: true);
// 1 minute offset
var epsilon = TimeSpan.FromMinutes(1);
await TestExpire(DateTime.Now + epsilon, expectFailure: false);
await TestExpire(DateTime.UtcNow + epsilon, expectFailure: false);
await TestExpire(DateTime.Now - epsilon, expectFailure: true);
await TestExpire(DateTime.UtcNow - epsilon, expectFailure: true);
}