alt Hacker Newsyes and no. You are correct the REPL provides more interactivity. However the downside is you can break something that used to work while make something else work.
There is no reason you can have a REPL and unit tests in the same. Every change results in running all the tests. (of course most changes are syntax error - just "if foo()" is 7 syntax errors. ) I've seen various attempts of this over the years, but quickly your code becomes more complex than the computer can run while you type and you fall back to running most of the tests after in some way.
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I think we're largely in agreement here. Unit tests and REPLs serve different purposes and are poor substitutes for each other; red_admiral was arguing that unit tests obviate the need for REPLs.
>I've seen various attempts of this over the years, but quickly your code becomes more complex than the computer can run while you type and you fall back to running most of the tests after in some way.
That does not match my experience with lisp.
REPL isn't just more ineractive, it's open ended.
I.e. you could execute a unit test in a REPL (after e.g. loading the test), but you can't run a REPL in a unit test - you can debug a test and maybe do some REPL like things, but, it's not the same at all...
You also can't write a unit test in a unit test, you can in a REPL.
Heck, an AI chatbot is a (non deterministic) REPL (it reads, evaluates, and prints something)...
Like others were saying, they are different, i.e. nothing at all alike, tests do not obviate REPLs...