public void NoCredentialsOnContext()
{
var request = new AssumeRoleRequest()
{
DurationSeconds = 0 // invalid value for DurationSeconds - credentials will be null when retrying request
};
var credentials = new STSAssumeRoleAWSCredentials(new AmazonSecurityTokenServiceClient(), request);
var s3Client = new AmazonS3Client(credentials);
AssertExtensions.ExpectException(() => { s3Client.ListBuckets(); }, typeof(AmazonSecurityTokenServiceException), new Regex("3 validation errors detected"));
}