My take on this problem would be:
- Provide a list to select one/multiple test cases.
- Provide "data-info" filters: what do you want to see mainly in the graph (in order to avoid an unreadable graph with thousands of lines)
- Provide a date filter: you rarely want to views years and years of data
Then, display:
- A graph with the "data-info" for all the test cases: and also being able to see easily the values in the graph (like Google Charts API graphs)
- Maybe some short insight about the data: a short text to resume the data
- A sortable-table (click to the legend name to sort) to view all the data individually in order to be able to review everything one by one
So here is a quick mock-up of this:

Quick notes:
- Save the settings parameters so the user doesn't have to re-select everything
- Allow to sort (and maybe search) in the table for easy reviewing
- Maybe add an indicator next to a test case if it reaches critical errors (for example, a fail/success rate too bad) to quickly show that this test has some issues
In conclusion, this kind of UI allows
- Quick and easy review of data
- Quick and easy customization to review precise data cases
- Quick overview thanks to the graph
- Detailed overview thanks to the table
So that should provide a rather nice user experience, I hope. :)
You can also check Google Public Data Explorer that provides similar "Choose what data you want and review"-UI.