How to set up .cabal test-suite when test file and the file under test is in different folder

Question

I am trying to structure my simple project in a way that it's easy for me to develop in the future. Basically I've used cabal init to get the basic stuff, then I created a src folder, inside that i created a main folder and a test folder, the main is for holding all source code and the test is to put all test source code. Inside .cabal I have the following:

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test-suit Test
  type:           exitcode-stdio-1.0
  hs-source-dirs: src/test
  main-is:        Test.hs
  build-depends:  base

executable Finance
  hs-source-dirs: src/main
  main-is:        Main.hs
  build-depends:  base

There are only three files Main.hs, Methods.hs, Test.hs. The Methods.hs is imported in Main.hs to get executed, and the Test.hs imports Methods.hs and tests the methods. My goal is to be able to do cabal --enable-tests configure then cabal build then cabal test then cabal install. But at the build stage I'm getting the error

src/test/Test.hs:2:8:
  Could not find module `Methods`
  Use -v to see a list of the files search for.

How do I let cabal know where Methods.hs is? Also, is there a better way to set the project up?

Answer 1

Looks like you just need to add src/main to hs-source-dirs for test suit.

Also you can create a library with Methods module and make both the executable and test suite depend on the library.

There are tons of examples on hackage, e.g. doctest It's test suit "spec" uses hs-source-dirs and test suit "doctests" uses a library. The first approach allows to test interval functions, that are not exported by the library.