Add some basic tests for this library (#20)

CHANGELOG.md

@@ -11,6 +11,7 @@ New features:
 Bugfixes:
 
 Other improvements:
+- Added tests (#20 by @ntwilson) 
 
 ## [v5.0.0](https://github.com/purescript-contrib/purescript-now/releases/tag/v5.0.0) - 2021-02-26
 

bower.json

@@ -20,6 +20,12 @@
     "purescript-effect": "^3.0.0"
   },
   "devDependencies": {
-    "purescript-console": "^5.0.0"
+    "purescript-assert": "^5.0.0",
+    "purescript-console": "^5.0.0",
+    "purescript-either": "^5.0.0",
+    "purescript-exceptions": "^5.0.0",
+    "purescript-node-process": "^8.0.0",
+    "purescript-prelude": "^5.0.0",
+    "purescript-transformers": "^5.0.0" 
   }
 }

spago.dhall

@@ -1,5 +1,16 @@
 { name = "now"
-, dependencies = [ "console", "datetime", "effect", "psci-support" ]
+, dependencies =
+  [ "assert"
+  , "console"
+  , "datetime"
+  , "effect"
+  , "either"
+  , "exceptions"
+  , "node-process"
+  , "prelude"
+  , "psci-support"
+  , "transformers"
+  ]
 , packages = ./packages.dhall
 , sources = [ "src/**/*.purs", "test/**/*.purs" ]
 }

test/Main.purs

@@ -2,10 +2,63 @@ module Test.Main where
 
 import Prelude
 
+import Control.Monad.Error.Class (try)
+import Control.Monad.State (StateT, execStateT, lift, modify)
+import Data.Either (Either(..))
+import Data.Time.Duration (Minutes(..))
 import Effect (Effect)
-import Effect.Class.Console (log)
+import Effect.Class.Console (log, logShow)
+import Effect.Exception (throw)
+import Effect.Now (getTimezoneOffset, now, nowDate, nowTime)
+import Node.Process (exit)
+import Test.Assert (assert, assert')
+
+type FailedTestCount = Int
+type Test = StateT FailedTestCount Effect Unit
+
+test :: String -> Effect Unit -> Test
+test name body = 
+  try (lift body) >>= case _ of
+    Right _ -> log ("✔️  " <> name)
+    Left err -> do 
+      log ("❌  " <> name)
+      logShow err
+      void $ modify (_ + 1)
+
+assertDoesNotThrow :: ∀ a. Effect a -> Effect Unit
+assertDoesNotThrow action = try action >>= case _ of
+  Right _ -> pure unit
+  Left err -> do throw ("Expected to not throw an exception, but one was thrown.\n" <> show err)
+
+
+timeAdvances :: ∀ time. Show time => Ord time => Effect time -> String -> Test
+timeAdvances getTime name = test ("time advances with " <> name) do
+  startTime <- getTime
+  endTime <- getTime
+  assert' (show endTime <> " should be greater than than " <> show startTime) $ endTime >= startTime 
+
+canGetTheCurrentTime :: Test
+canGetTheCurrentTime = test "can get the current time" do 
+  assertDoesNotThrow nowTime
+
+offsetSeemsSensible :: Test
+offsetSeemsSensible = test "UTC offset between -13:00 and +15:00" do
+  minutes <- getTimezoneOffset
+  assert $ between lbound ubound minutes
+
+  where
+    lbound = Minutes $ (-13.0) * minPerHour
+    ubound = Minutes $ 15.0 * minPerHour
+    minPerHour = 60.0
+
 
 main :: Effect Unit
 main = do
-  log "🍝"
-  log "You should add some tests."
+  failedTests <- flip execStateT 0 do 
+    timeAdvances now "now"
+    timeAdvances nowDate "nowDate"
+    canGetTheCurrentTime
+    offsetSeemsSensible
+
+  exit failedTests
+