Automated unit tests or folding Array Unit to Unit [SOLVED]

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#1

Hi everybody! For my unit tests I wanted to read a json file with all test cases and run them with something like

runTestCase tc =
  test "a check" do
    Assert.equal tc.request.body tc.response.body

main :: Effect Unit
main =
  launchAff_ do
    rs <- readOrThrow "./test/Server/testCases.json"
    ts <- mkTestCase "./test/Server" `traverse` rs
    runTestWith runTest do
      suite "Tests" do
        runTestCase `traverse` ts

The error is Could not match type Array Unit with type Unit.
Does somebody know how to resolve this?

#2

It would be great if you could show us the full code (e.g. how are mkTestCase and runTestCase defined?) and full error too.

#3

I’m pretty sure the issue is with your last line. runTestCase looks like TestCase -> Effect Unit, and ts looks like an Array TestCase, so when you call traverse, you end up with an Effect (Array Unit). You can only put an effect on a line by itself without binding it to a name if it’s type is Effect Unit. So to resolve it, you could either do

_ <- runTestCase `traverse` ts
pure unit

or just

runTestCase `traverse_` ts
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#4

Yeah, that’s it. Thanks! I was the whole time looking for some kind of unit concat. :roll_eyes:

1 Like