Our team writes unittests for our python projects. Besides that, we have a tool that allows us to run scripted API tests (we can make requests and evaluate the result, passing or failing the test).
I am looking for a tool that helps the team to write acceptance tests for every ticket we do (primary objective), and then store these tests to start our regression test repository (secondary objective).
The problem is that not every ticket we do is API test-able, and sometimes I feel unittests are not enough (sometimes we need grey or black box tests). Some of our services don't have public APIs and they interact with other services in a lower level.
For example, we could have a ticket to change an internal function, but this should not affect our API response (we have tests to check this). Unittests could supposedly test this specific function, but this function can be called in other parts of our code (and even in other projects), so there's no way to write an unittest to check if this change won't break stuff across all of our services.
I was taking a look at Fitnesse and I was wondering: can Fitnesse fill in the gap between unittests and REST API testing, with the so called "acceptance tests"? What type of input/output can Fitnesse take?