add test scaffold and first test

default.nix

@@ -1,32 +1,23 @@
-{ mkDerivation, aeson, base, base16-bytestring, base64-bytestring
-, bytestring, case-insensitive, clock, containers, extra, HsYAML
-, http-api-data, http-types, iproute, mtl, network, opaleye
-, optparse-applicative, postgresql-simple
-, postgresql-simple-migration, product-profunctors, profunctors
-, pureMD5, random-bytestring, servant, servant-rawm, servant-server
-, stdenv, stm, text, time, wai, wai-logger, wai-middleware-throttle
-, warp
-}:
-mkDerivation {
-  pname = "mateamt";
-  version = "0.0.0.0";
-  src = ./.;
-  isLibrary = true;
-  isExecutable = true;
-  libraryHaskellDepends = [
-    aeson base base16-bytestring base64-bytestring bytestring
-    containers extra http-api-data http-types mtl opaleye
-    postgresql-simple product-profunctors profunctors pureMD5
-    random-bytestring servant servant-rawm servant-server stm text time
-    wai wai-logger warp
-  ];
-  executableHaskellDepends = [
-    base base16-bytestring bytestring case-insensitive clock containers
-    HsYAML iproute mtl network opaleye optparse-applicative
-    postgresql-simple postgresql-simple-migration servant
-    servant-server stm text time wai wai-logger wai-middleware-throttle
-    warp
-  ];
-  description = "A whole new matemat";
-  license = stdenv.lib.licenses.agpl3;
+{ # Fetch the latest haskell.nix and import its default.nix
+  haskellNix ? import (builtins.fetchTarball "https://github.com/input-output-hk/haskell.nix/archive/master.tar.gz") {}
+
+# haskell.nix provides access to the nixpkgs pins which are used by our CI,
+# hence you will be more likely to get cache hits when using these.
+# But you can also just use your own, e.g. '<nixpkgs>'.
+, nixpkgsSrc ? haskellNix.sources.nixpkgs-2009
+
+# haskell.nix provides some arguments to be passed to nixpkgs, including some
+# patches and also the haskell.nix functionality itself as an overlay.
+, nixpkgsArgs ? haskellNix.nixpkgsArgs
+
+# import nixpkgs with overlays
+, pkgs ? import nixpkgsSrc nixpkgsArgs
+}: pkgs.haskell-nix.project {
+  # 'cleanGit' cleans a source directory based on the files known by git
+  src = pkgs.haskell-nix.haskellLib.cleanGit {
+    name = "mateamt";
+    src = ./.;
+  };
+  # Specify the GHC version to use.
+  compiler-nix-name = "ghc8103"; # Not required for `stack.yaml` based projects.
 }

mateamt.cabal

@@ -19,7 +19,7 @@ flag develop
   manual:            True
 
 executable mateamt
-  main-is:             Main.hs
+  main-is:             AppMain.hs
   other-modules:       AppTypes
                      , AppTypes.Configuration
                      , Janitor
@@ -120,3 +120,26 @@ library
   ghc-options:       -Wall
   if flag(develop)
     cpp-options:       -DDEVELOP
+
+test-suite spec
+  type:              exitcode-stdio-1.0
+  main-is:           Main.hs
+  hs-source-dirs:      test
+  ghc-options:         -Wall
+  build-depends:       base
+                     , mateamt
+                     , hspec
+                     , hspec-wai
+                     , hspec-wai-json
+                     , warp
+                     , wai
+                     , pg-transact
+                     , tmp-postgres
+                     , bytestring
+                     , resource-pool
+                     , postgresql-simple
+  other-modules:       TestUtil
+                     , Spec
+                     , MainSpec
+  default-language:    Haskell2010
+  build-tool-depends: hspec-discover:hspec-discover

test/Main.hs

@@ -0,0 +1,8 @@
+{-# LANGUAGE PackageImports #-}
+module Main where
+
+import Test.Hspec
+import qualified Spec
+
+main :: IO ()
+main = hspec Spec.spec

test/MainSpec.hs

@@ -0,0 +1,20 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE PackageImports #-}
+module MainSpec where
+
+import Database.PostgreSQL.Transact
+import Database.PostgreSQL.Simple (Only(..))
+
+import Test.Hspec
+
+import Control.Monad.IO.Class (liftIO)
+
+-- internal imports
+
+import qualified "mateamt" Util as LibUtil
+import TestUtil
+
+spec = describeDB (const $ return ()) "Initialize DB" $
+  itDB "call initialization script" $ do
+    conn <- getConnection
+    liftIO $ shouldReturn (LibUtil.initDB conn) ()

test/Spec.hs

@@ -0,0 +1 @@
+{-# OPTIONS_GHC -F -pgmF hspec-discover -optF --module-name=Spec #-}

test/TestUtil.hs

@@ -0,0 +1,50 @@
+{-# LANGUAGE RecordWildCards #-}
+module TestUtil where
+
+import           Control.Exception
+import           Control.Monad
+import qualified Data.ByteString.Char8        as BSC
+import           Data.Pool
+import qualified Database.Postgres.Temp       as Temp
+import           Database.PostgreSQL.Simple
+import           Database.PostgreSQL.Transact
+import           Test.Hspec
+
+describeDB :: (Connection -> IO ()) -> String -> SpecWith TestDB -> Spec
+describeDB migrate str =
+  beforeAll (setupDB migrate) . afterAll teardownDB . describe str
+
+setupDB :: (Connection -> IO ()) -> IO TestDB
+setupDB migrate = do
+  tempDB <- either throwIO return =<< Temp.start
+  putStrLn $ BSC.unpack $ Temp.toConnectionString tempDB
+  pool <- createPool
+    (connectPostgreSQL (Temp.toConnectionString tempDB))
+    close
+    1
+    100000000
+    50
+  withResource pool migrate
+  return TestDB {..}
+
+teardownDB :: TestDB -> IO ()
+teardownDB TestDB {..} = do
+  destroyAllResources pool
+  void $ Temp.stop tempDB
+
+withPool :: TestDB -> (Connection -> IO a) -> IO a
+withPool testDB = withResource (pool testDB)
+
+itDB :: String -> DB a -> SpecWith TestDB
+itDB msg action = it msg $ void . withDB action
+
+withDB :: DB a -> TestDB -> IO a
+withDB action testDB =
+  withResource (pool testDB) (runDBTSerializable action)
+
+data TestDB = TestDB
+  { tempDB     :: Temp.DB
+  -- ^ Handle for temporary @postgres@ process
+  , pool :: Pool Connection
+  -- ^ Pool of 50 connections to the temporary @postgres@
+  }