Do you prefer a quicker test-driven development turnaround, and have battery and CPU cycles to spare? Check out this library that lets you have compile-time unit tests, whose failures are highlighted as syntax errors in your favorite editor!
raco pkg install examples
The library is inspired by Lean's #guard commands, but they're not equivalent. For example, Lean can make statements involving free variables. But Racket can run arbitrary code!
At the moment, the library has most of RackUnit's basic checks. Pull requests are welcome (especially help with scribblings if there are problems; I'm technology-illerate and this is my first time trying to use scribble to document 
)