Allow test results to be absent

With plan branches, we have this problem :

• trunk has no tests
• branch has tests

If we configure Maven with 'The build will produce test results.' or JUnit Parser task, the trunk will fail, but if we disable tests parsing, branch will not display tests results.

It would be better to have 2 levels : 'The build MUST produce test results' (current behavior) and 'The build MAY produce test results' (will not fail if there is no tests but will parse them if they exist)