When building a maven 2 based project using the maven2 form, then the junit
trandgraf is only updated on successfull builds. Whenever a build fails the
trend graf is not updated.

So If I have set my unittest to fail the build, then I only get grafs when I
have no errors at all.

However the data is correctly captured since once a build makes it, then all
intermediate failed builds are included in the trend graph.