Add support for generating test-suite.

[m-renaud]

Overview

Support generating a test-suite for libraries from cabal init.

Partially addresses #5705.

Changes

Two new flags:
--tests :: Bool
--test-dir :: [String] (same behaviour as srcDirs)

Interactive Prompt Behaviour

You will only get asked about generating a test suite if it is a Library or LibraryAndExecutable. The rationale for this is because testing modules that are only part of an executable is more complicated to set up then just depending on the library.

If you select "no" for generating a test suite, you won't be asked for the test directory.

Example Invocation

$ cabal init -n --is-libandexe --tests --test-dir=test --source-dir=src

Guessing dependencies...

Generating LICENSE...
Warning: unknown license type, you must put a copy in LICENSE yourself.
Generating Setup.hs...
Generating CHANGELOG.md...
Generating src/Main.hs...
Generating test/MyLibTest.hs...
Generating initsample.cabal...

initsample.cabal

cabal-version:       >=1.10
-- Initial package description 'initsample.cabal' generated by 'cabal
-- init'.  For further documentation, see
-- http://haskell.org/cabal/users-guide/

name:                initsample
version:             0.1.0.0
-- synopsis:
-- description:
-- bug-reports:
-- license:
license-file:        LICENSE
author:              Matt Renaud
maintainer:          [email protected]
-- copyright:
-- category:
build-type:          Simple
extra-source-files:  CHANGELOG.md

library
  -- exposed-modules:
  -- other-modules:
  -- other-extensions:
  build-depends:       base >=4.11 && <4.12
  hs-source-dirs:      src
  default-language:    Haskell2010

executable initsample
  main-is:             Main.hs
  -- other-modules:
  -- other-extensions:
  build-depends:       base >=4.11 && <4.12
  hs-source-dirs:      src
  default-language:    Haskell2010

test-suite initsample-test
  default-language:    Haskell2010
  type:                exitcode-stdio-1.0
  hs-source-dirs:      test
  main-is:             MyLibTest.hs
  build-depends:       base >=4.11 && <4.12

TODO

• Update changelog
• Actually test MyLib.hs once cabal init improvements: application-dir and creating library hs file #5740 is merged

---

Please include the following checklist in your PR:

• Patches conform to the coding conventions.
• Any changes that could be relevant to users have been recorded in the changelog.
• The documentation has been updated, if necessary.
• If the change is docs-only, [ci skip] is used to avoid triggering the build bots.

Please also shortly describe how you tested your change. Bonus points for added tests!

[23Skidoo]

LGTM, feel free to merge once it's green.

[23Skidoo]

Merged, thanks!