[brabel]

With Jetbrains IDEs (IntelliJ, Webstorm, CLion) you can run a "sketch" that can "see" any module in your project. I use that a lot in Java/Groovy/Kotlin/Rust and it feels much superior to a REPL because I can write not just one-liners, but larger amounts of code, with all the features of the IDE like auto-completion, inline docs, syntax checking etc.

[zozbot234]

A test suite facility can also be used like this. And Rust adds any "examples" you write in the code (with proper doc formatting) to the test suite, as mentioned elsewhere.

[brabel]

A test suite has a different use case... REPLs/Sketches are useful for exploration... both of your own design and of libraries you're using. Tests can be used for this as well, but it's not as convenient when you're very "early" in your exploration or have no code yet to test at all.