Quality is delighting customers
1. Graph loads successfully (Chart/Bars)
2. Correct values displayed with respect to its Pivot table (values of the graph x-axis & y-axis matches its table values)
3. Graph should have options (eg: download, print)
4. If the Graph is hyper linked (on click, navigates to some other page), it should redirect to the expected page
Negative - TCs
1. Graph does not load (Image not loaded properly with a X icon)
2. Colour combinations mismatch
Can think of only these for now
Also, you should test how the data variation affect the graph. The chart has to response immediately to the data changes, especially in SaaS application. Usually you need to check database in cooperation with tested data on report.
Turn the graph upside down!
you need to check with all possible combinations of data. For EG: Check with Boundary value analysis, Higher and lower data. Check with maximum combinations and also verify the values with db as mentioned above.