Test output format
By default, test results look like this:

However, the tester provides two additional options.
Compact
The compact output removes unnecessary information and shows each completed test
with a dot, and the failed test with the letter E:

All failed tests will be printed at the end of the output.
Teamcity
Output in Teamcity format allows you to integrate tests into TeamCity and JetBrains IDEs. Essentially, this is the default format, but with additional service messages that are interpreted by TeamCity/IDEs.
Have an idea?
Writing custom test output formats is straightforward, see y/testing/reporter.sp for an example.
If you have ideas for new output formats, create an issue on GitHub or submit a PR!