Adding tests

haskell-template does not include tests by default (see Philosophy), but you may add them as follows:

• Split any logic code out of Main.hs into, say, a Lib.hs.
• Correspondingly, add other-modules: Lib to the “shared” section of your cabal file.
• Add tests/Spec.hs (example below):

  module Main where
  
  import Lib qualified
  import Test.Hspec (describe, hspec, it, shouldContain)
  
  main :: IO ()
  main = hspec $ do
    describe "Lib.hello" $ do
      it "contains the world emoji" $ do
        toString Lib.hello `shouldContain` "🌎"

• Add the tests stanza to the cabal file:

  test-suite tests
      import:         shared
      main-is:        Spec.hs
      type:           exitcode-stdio-1.0
      hs-source-dirs: tests
      build-depends:  hspec

• Update hie.yaml accordingly; for example, by adding,

    - path: "tests"
      component: "test:tests"

• Add the test command to the mission-control scripts section of the flake file

    mission-control.scripts = {
      test = {
        description = "Run all tests";
        exec = ''
           ghcid -c "cabal repl test:tests" -T :main
        '';
        };
    };

• Commit your changes to Git, and test it out by running , test from the (reloaded) dev shell.