Add test.

Author: cdepillabout

test/cabal-doctests/Doctests.hs

@@ -0,0 +1,16 @@
+module Main where
+
+import Build_doctests (flags, pkgs, module_sources)
+import Data.Foldable (traverse_)
+import System.Environment (unsetEnv)
+import Test.DocTest (doctest)
+
+main :: IO ()
+main = do
+  putStrLn ""
+  traverse_ putStrLn args -- optionally print arguments
+  unsetEnv "GHC_ENVIRONMENT" -- see 'Notes'; you may not need this
+  doctest args
+  where
+    args :: [String]
+    args = flags ++ pkgs ++ module_sources -- ++ ["-v"]

test/cabal-doctests/Lib.hs

@@ -0,0 +1,18 @@
+module Lib
+    ( someFunc
+    ) where
+
+import Data.Aeson (encode)
+import Paths_cabal_doctests_test (version)
+
+-- |
+-- >>> 1 + 1
+-- 2
+--
+-- >>> version
+-- Version {versionBranch = [0,1,0,0], versionTags = []}
+--
+-- >>> encode (Just 1 :: Maybe Int)
+-- "1"
+someFunc :: IO ()
+someFunc = putStrLn "someFunc"

test/cabal-doctests/Setup.hs

@@ -0,0 +1,6 @@
+module Main where
+
+import Distribution.Extra.Doctest (defaultMainWithDoctests)
+
+main :: IO ()
+main = defaultMainWithDoctests "doctests"

test/cabal-doctests/cabal-doctests-test.cabal

@@ -0,0 +1,29 @@
+cabal-version: 1.12
+
+name:           cabal-doctests-test
+version:        0.1.0.0
+build-type:     Custom
+
+custom-setup
+ setup-depends:
+   base >= 4 && <5,
+   Cabal,
+   cabal-doctest >= 1 && <1.1
+
+library
+  exposed-modules: Lib
+  other-modules: Paths_cabal_doctests_test
+  build-depends:
+      base >=4.7 && <5,
+      aeson
+  default-language: Haskell2010
+
+test-suite doctests
+  type: exitcode-stdio-1.0
+  main-is: Doctests.hs
+  ghc-options: -threaded -rtsopts -with-rtsopts=-N
+  build-depends:
+      base >=4.7 && <5
+    , doctest
+    , cabal-doctests-test
+  default-language: Haskell2010

test/cabal-doctests/default.nix

@@ -0,0 +1,73 @@
+# Test a package set
+{ stdenv, util, cabalProject', haskellLib, gmp6, zlib, recurseIntoAttrs }:
+
+with stdenv.lib;
+
+let
+  project =
+    cabalProject' {
+      src = haskellLib.cleanGit { src = ../..; subDir = "test/cabal-doctests"; };
+      index-state = "2020-01-26T00:00:00Z";
+      modules = [
+        {
+          # This is needed for the doctest library to be built.  Without it, you
+          # get an error like the following:
+          #
+          # Configuring library for doctest-0.16.2..
+          # Error:
+          #     The following packages are broken because other packages they
+          #     depend on are missing. These broken packages must be rebuilt
+          #     before they can be used.
+          #     - installed package ghc-8.6.5 is broken due to missing package
+          #       terminfo-0.4.1.2
+          nonReinstallablePkgs =
+            [ "rts" "ghc-heap" "ghc-prim" "integer-gmp" "integer-simple" "base"
+              "deepseq" "array" "ghc-boot-th" "pretty" "template-haskell"
+              "ghc-boot"
+              "ghc" "Cabal" "Win32" "array" "binary" "bytestring" "containers"
+              "directory" "filepath" "ghc-boot" "ghc-compact" "ghc-prim"
+              "ghci" "haskeline"
+              "hpc"
+              "mtl" "parsec" "process" "text" "time" "transformers"
+              "unix" "xhtml"
+              "stm" "terminfo"
+            ];
+
+          packages.cabal-doctests-test.components.tests.doctests.isDoctest = true;
+        }
+      ];
+    };
+
+  packages = project.hsPkgs;
+
+in
+
+recurseIntoAttrs {
+  ifdInputs = {
+    inherit (project) plan-nix;
+  };
+
+  # Used for testing externally with nix-shell (../tests.sh).
+  # This just adds cabal-install to the existing shells.
+  # test-shell = util.addCabalInstall packages.cabal-doctests-test.components.all;
+
+  run = stdenv.mkDerivation {
+    name = "cabal-doctests-test";
+
+    buildCommand = ''
+      printf "Checking that doctest tests have run ... " >& 2
+      doctest_output="${packages.cabal-doctests-test.checks.doctests}"
+      test -f "$doctest_output"
+      cat "$doctest_output" >& 2
+
+      touch $out
+    '';
+
+    meta.platforms = platforms.all;
+
+    passthru = {
+      # Used for debugging with nix repl
+      inherit project packages;
+    };
+  };
+}

test/default.nix

@@ -167,6 +167,7 @@ let
     ghc-options-stack = haskell-nix.callPackage ./ghc-options/stack.nix {};
     exe-only = haskell-nix.callPackage ./exe-only { inherit util; };
     stack-source-repo = haskell-nix.callPackage ./stack-source-repo {};
+    cabal-doctests = haskell-nix.callPackage ./cabal-doctests { inherit util; };
 
     unit = unitTests;
   };