update test a bit

Author: hdgarrood

test/Main.purs

@@ -1,9 +1,11 @@
 module Test.Main where
 
 import Prelude
+import Control.Apply
 import Control.Bind
 
 import Control.Monad.Eff.Console
+import Control.Monad.Eff.Console.Unsafe
 
 import Node.Encoding (Encoding(UTF8))
 import Node.Buffer as Buffer
@@ -12,7 +14,19 @@ import Node.ChildProcess.Signal
 import Node.Stream (onData)
 
 main = do
+  log "spawns processes ok"
+  spawnLs
+
+  log "emits an error if executable does not exist"
+  nonExistentExecutable $ do
+    log "all good."
+
+spawnLs = do
   ls <- spawn "ls" ["-la"] defaultSpawnOptions
   onExit ls \exit ->
       log $ "ls exited: " <> show exit
   onData (stdout ls) (Buffer.toString UTF8 >=> log)
+
+nonExistentExecutable done = do
+  ch <- spawn "this-does-not-exist" [] defaultSpawnOptions
+  onError ch (\err -> logAny err *> done)