Run from a command line ruby test/unit/my_model.rb
to run one test suite. You can also use a debugger, such as (wrapped by) RubyMine or pry, to stop on a specific test case and look at the log.
But if a sledge-hammer does not solve the problem, you can use tweezers: config.logger.level = Logger::WARN
in your test.rb
, from Set logging levels in Ruby on Rails