Spotfire tool is a dynamic driven tool. Spotfire tool does not expose data values directly on the link you provided. I see the following options for testing.
1. Do a manual test of the graphs with tester and visual inspection.
2. Do a bitmap checkpoint test with fix data amounts. Basically bitmap check point in QTP will only do a pixel compare with previous capture bitmap and all of the values will have to be the same.
3. Go to the Dashboard details and pull the data out of the tables provide.
4. Export to PDF and attempt to pull details from report. This area did not work when I was testing so I could not test it.
5. Work with the developer to get the SDK to expose children objects and values. This is only a guess since we cannot get access to the underlining SDK.