Currently, the Steps page shows the output from test runs in color - but the Tests page, which shows all the run's failures - doesn't handle ANSI colors
This makes viewing the output of your failed tests harder. Colors are useful UI, they should be supported!
The current recommendation is disabling color output for tests: https://support.circleci.com/hc/en-us/articles/360003108933-ANSI-color-codes-appearing-in-test-results - but that makes viewing diffs (and other test output) harder.