It is a good idea to use an index for testing purposes, especially when you need to index new data and you are not familiar with its format. You should consider creating an index just for this purpose as you are crafting solutions to load data into Splunk.
When loading data for the first time into Splunk, especially if it is a custom sourcetype, it often will not be loaded properly with all the fields recognized accurately. Performing a one-time load into a temporary Splunk index from a file will ensure that any problems or incorrect field extractions won't cause dirty data to be loaded and stored with clean, tested data.
This is especially crucial when you know you will have to transform the data, for instance, using props.conf and transforms.conf. During that development process, there could be many different configurations that need to be tested and...