The lua-based test harness is pretty nice, but it could be nicer. Here are some ways we could improve it:

• /CleanUpTestNames
• When you use check(EXPRESSION) and it fails, what you get in the logfile is unhelpful
• The command form of check has too many arguments, and is much too clever about type overloading
• indir() doesn't work the way one might expect it to
• The default test workspace should be a subdirectory of the test dir, not the test dir (there's all sorts of clutter in the test dir)
• Better tools for pattern matching command output
• Run more than one test in parallel on multi-CPU machines (extra points for noticing being run under make -j and participating in the gmake "job server" algorithm)
• Nathaniel wants a "run the most recently modified test" option
• Some way of re-running all failed tests would be good

See also OldTestHarnessIssues from the days of autotest.