expectErr      bool
	}{
		{[]byte(`<S3Key><FilterRule><Name>suffix</Name><Value>Hello/世界</Value></FilterRule><FilterRule><Name>suffix</Name><Value>foo/bar</Value></FilterRule></S3Key>`), nil, true},
		{[]byte(`<S3Key><FilterRule><Name>prefix</Name><Value>Hello/世界</Value></FilterRule><FilterRule><Name>prefix</Name><Value>foo/bar</Value></FilterRule></S3Key>`), nil, true},

	}

	return NewPattern(prefix, suffix)
}

// S3Key - represents elements inside <S3Key>...</S3Key>
type S3Key struct {
	RuleList FilterRuleList `xml:"S3Key,omitempty" json:"S3Key,omitempty"`
}

// MarshalXML implements a custom marshaller to support `omitempty` feature.
func (s3Key S3Key) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
	if s3Key.RuleList.isEmpty() {
		return nil
	}

	// Sample bucket notification.
	bucketNotificationBuf := `<NotificationConfiguration><QueueConfiguration><Event>s3:ObjectCreated:Put</Event><Filter><S3Key><FilterRule><Name>prefix</Name><Value>images/</Value></FilterRule></S3Key></Filter><Id>1</Id><Queue>arn:minio:sqs:us-east-1:444455556666:webhook</Queue></QueueConfiguration></NotificationConfiguration>`
	// generate a random bucket Name.