I wrote a simple set of test-cases for my lisp implementation, and use the TAP format for the output. In my case I pipe to "tapview", by ESR, to visualize the results. The raw output is otherwise pretty basic:

      TAP version 14
      ok tst:zero:1
      ok tst:zero:2
      ..
      ok union:1
      ok union:2
      ok year:len
      1..215

Tapview is pretty portable, and works well as a simple output visualizer turning my view into:

      ./yal examples/lisp-tests.lisp | _misc/tapview
      ...........................................................
      215 tests, 0 failures.