[#47] Add doctest tests to co-log-core package (#55)

* [#47] Add `doctest` tests to `co-log-core` package

* Fix warning

* Fix review and format issues

* Add doctests for Colog.Core.IO module

co-log-core/co-log-core.cabal

@@ -45,8 +45,8 @@ library
   other-extensions:    CPP
 
 test-suite doctest
-  build-depends: base, doctest ^>= 0.16.0
-  default-language: Haskell2010
-  hs-source-dirs: tests
-  main-is: doctest.hs
-  type: exitcode-stdio-1.0
+  build-depends:        base, doctest ^>= 0.16.0
+  default-language:     Haskell2010
+  hs-source-dirs:       test
+  main-is:              Doctests.hs
+  type:                 exitcode-stdio-1.0

co-log-core/src/Colog/Core/Action.hs

@@ -336,7 +336,6 @@ foo.g.f2
 >>> unLogAction (logToStdout =>> f =>> g) "foo"
 foo.g.f1
 foo.g.f2
-
 -}
 extend :: Semigroup msg => (LogAction m msg -> m ()) -> LogAction m msg -> LogAction m msg
 extend f (LogAction action) = LogAction $ \m -> f $ LogAction $ \m' -> action (m <> m')

co-log-core/src/Colog/Core/IO.hs

@@ -10,16 +10,27 @@ import Control.Monad.IO.Class (MonadIO, liftIO)
 import System.IO (Handle, IOMode( AppendMode ), hPutStrLn, stderr, withFile)
 import Colog.Core.Action (LogAction (..))
 
+{- | Action that prints 'String' to stdout.
 
-{- | Action that prints 'String' to stdout. -}
+>>> unLogAction logStringStdout "foo"
+foo
+-}
 logStringStdout :: MonadIO m => LogAction m String
 logStringStdout = LogAction (liftIO . putStrLn)
 
-{- | Action that prints 'String' to stderr. -}
+{- | Action that prints 'String' to stderr.
+
+>>> unLogAction logStringStderr "foo"
+foo
+-}
 logStringStderr :: MonadIO m => LogAction m String
 logStringStderr = logStringHandle stderr
 
-{- | Action that prints 'String' to 'Handle'. -}
+{- | Action that prints 'String' to 'Handle'.
+
+>>> (unLogAction . logStringHandle) stderr "foo"
+foo
+-}
 logStringHandle :: MonadIO m => Handle -> LogAction m String
 logStringHandle handle = LogAction $ liftIO . hPutStrLn handle
 
@@ -29,10 +40,18 @@ file only once at the start of the application and write to 'Handle' instead of
 opening file each time we need to write to it.
 
 Opens file in 'AppendMode'.
+>>> logger action = unLogAction action "foo"
+>>> withLogStringFile "/dev/stdout" logger
+foo
 -}
 withLogStringFile :: MonadIO m => FilePath -> (LogAction m String -> IO r) -> IO r
 withLogStringFile path action = withFile path AppendMode $ action . logStringHandle
 
-{- | Lifts a LogAction over IO into a more general Monad. -}
+{- | Lifts a LogAction over IO into a more general Monad.
+
+>>> logToStdout = LogAction putStrLn
+>>> unLogAction (liftLogIO logToStdout) "foo"
+foo
+-}
 liftLogIO :: MonadIO m => LogAction IO msg -> LogAction m msg
 liftLogIO (LogAction action) = LogAction (liftIO . action)

co-log-core/tests/doctest.hs → co-log-core/test/Doctests.hs

@@ -5,4 +5,4 @@ module Main
 import Test.DocTest (doctest)
 
 main :: IO ()
-main = doctest ["-XInstanceSigs", "src"]
+main = doctest ["-XInstanceSigs", "src"]