Added doctests and compiler warnings

stack.yaml

@@ -15,7 +15,7 @@
 # resolver:
 #  name: custom-snapshot
 #  location: "./custom-snapshot.yaml"
-resolver: lts-8.14
+resolver: lts-14.20
 
 # User packages to be built.
 # Various formats can be used as shown in the example below.
@@ -63,4 +63,4 @@ extra-package-dbs: []
 # extra-lib-dirs: [/path/to/dir]
 #
 # Allow a newer minor version of GHC than the snapshot specifies
-# compiler-check: newer-minor
+# compiler-check: newer-minor

test/Doc.hs

@@ -0,0 +1,6 @@
+module Main (main) where
+
+import Test.DocTest
+
+main :: IO ()
+main = doctest [ "-XOverloadedStrings", "src" ]

validationt.cabal

@@ -39,3 +39,33 @@ library
                      , vector
   hs-source-dirs:      src
   default-language:    Haskell2010
+  ghc-options:         -fwarn-unused-binds
+                       -Wall
+                       -Wincomplete-uni-patterns
+                       -Wincomplete-record-updates
+                       -Wpartial-fields
+                       -Werror=missing-home-modules
+                       -Wmissing-home-modules
+                       -Widentities
+                       -Wredundant-constraints
+                       -Wmissing-export-lists
+
+test-suite doctest
+  type: exitcode-stdio-1.0
+  hs-source-dirs: test
+  ghc-options: -Wall
+  main-is: Doc.hs
+  build-depends:       base >=4.8 && < 5
+                     , aeson >= 1.0
+                     , doctest
+                     , containers
+                     , exceptions
+                     , lens
+                     , monad-control
+                     , mtl
+                     , QuickCheck
+                     , text
+                     , transformers
+                     , transformers-base
+                     , vector
+                     , doctest