Rails backtrace silencers do not work, while filters do

Question

Fresh Rails 4.2 set up. I want to suppress long error backtraces. In the following backtrace log first line would be enough for me, and next 4 could be removed

Answer 1

I had a similar problem, which was caused by this code in test_helper:

def MiniTest.filter_backtrace(backtrace, prefix=nil)
  backtrace
end

It was added to diagnose the error at some stage and overrides this. Removing that removed the backtrace.