public void AddPropertiesToPromote() { var sut = new MessageProperties { { MessagePropertiesExtensions.PROPERTIES_TO_PROMOTE_KEY, new List <PropertyValuePair>( new[] { new PropertyValuePair(BtsProperties.MessageType.QName, nameof(BtsProperties.MessageType)), new PropertyValuePair(BtsProperties.Operation.QName, nameof(BtsProperties.Operation)) }) } }; sut.AddPropertiesToPromote( new[] { new PropertyValuePair(BtsProperties.MessageType.QName, "overridden"), new PropertyValuePair(BtsProperties.InterchangeID.QName, nameof(BtsProperties.InterchangeID)) }); sut[MessagePropertiesExtensions.PROPERTIES_TO_PROMOTE_KEY].Should().BeOfType <List <PropertyValuePair> >().And.BeEquivalentTo( new[] { new PropertyValuePair(BtsProperties.MessageType.QName, "overridden"), new PropertyValuePair(BtsProperties.Operation.QName, nameof(BtsProperties.Operation)), new PropertyValuePair(BtsProperties.InterchangeID.QName, nameof(BtsProperties.InterchangeID)) }); }