My test suites are large, and write a lot of stuff to output as they go along (mostly from the code under test rather than the tests themselves). I run them using ConsoleLauncher. The tree report at the end of the run is useful. But the torrent of console output is usually not: it is very helpful to have output captured when diagnosing failures, but seeing reams out output for passing tests is not.

I believe that JUnit can capture standard output and error. It would be very useful if there was a flag i could give to ConsoleLauncher to tell it to do this, and write the results to one or more files, instead of the console. The simplest thing would be to write all output to a single file (whose contents would be the same as what i currently see in the console). Significantly more useful would to write the output of each test to its own file, to make it easier to find. Perhaps tests which write no output could not create files at all, not sure.

A potential quirk here is that much of this output is written using a logging framework (usually java.util.logging) with an appender which writes to standard output. It would be possible to configure logging differently in tests, but i would prefer not to have to do that - just capturing output as it is written with the default logging configuration is greatly preferable to me.

One thing that wouldn't be useful to me is separate files for standard output and standard error. There is not usually a huge semantic difference between the two, whereas the relative order of messages written across both is usually very important, and separating the files would discard that.

Is there already some way to do this? Would it be possible for me to write some sort of extension to do this, which i could use without modifying my test sources? If not, would this make a good feature?