public void SetOptionalFields_FormObject_ListFieldNumbers_Null() { string fieldNumber = "123"; FieldObject fieldObject = new FieldObject(fieldNumber); List <string> fieldNumbers = null; RowObject rowObject = new RowObject(); rowObject.AddFieldObject(fieldObject); FormObject formObject = new FormObject("1"); formObject.AddRowObject(rowObject); formObject.SetOptionalFields(fieldNumbers); Assert.IsFalse(formObject.IsFieldEnabled(fieldNumber)); Assert.IsFalse(formObject.IsFieldRequired(fieldNumber)); }