Add a piping test

src/Node/Stream.purs

@@ -78,9 +78,7 @@ onData r cb =
 -- | decoded using the given encoding. Note that this will fail if `setEncoding`
 -- | has been called on the stream.
 onDataString :: forall w eff. Readable w (err :: EXCEPTION | eff) -> Encoding -> (String -> Eff (err :: EXCEPTION | eff) Unit) -> Eff (err :: EXCEPTION | eff) Unit
-onDataString r enc cb = onData r $ \buf -> do
-  str <- unsafeInterleaveEff (Buffer.toString enc buf)
-  cb str
+onDataString r enc cb = onData r (cb <=< unsafeInterleaveEff <<< Buffer.toString enc)
 
 foreign import onDataEitherImpl :: forall w eff. (forall l r. l -> Either l r) -> (forall l r. r -> Either l r) -> Readable w eff -> (Either String Buffer -> Eff eff Unit) -> Eff eff Unit
 
@@ -149,3 +147,4 @@ setDefaultEncoding r enc = setDefaultEncodingImpl r (show enc)
 
 -- | End writing data to the stream.
 foreign import end :: forall r eff. Writable r eff -> Eff eff Unit -> Eff eff Unit
+

test/Main.js

@@ -28,3 +28,11 @@ exports.putImpl = function(str) {
     };
   };
 };
+
+exports.createGzip = require('zlib').createGzip;
+exports.createGunzip = require('zlib').createGunzip;
+
+exports.passThrough = function () {
+    var s = require('stream');
+    return new s.PassThrough();
+};

test/Main.purs

@@ -37,6 +37,9 @@ main = do
   log "setEncoding should not affect reading"
   testSetEncoding
 
+  log "test pipe"
+  testPipe
+
 testString :: String
 testString = "üöß💡"
 
@@ -71,3 +74,31 @@ testSetEncoding = do
       onDataEither r2 \(Left str) -> do
         assertEqual <$> Buffer.toString enc buf <*> pure testString
         assertEqual str testString
+
+testPipe = do
+  sIn   <- passThrough
+  sOut  <- passThrough
+  zip   <- createGzip
+  unzip <- createGunzip
+
+  log "pipe 1"
+  sIn `pipe` zip
+  log "pipe 2"
+  zip `pipe` unzip
+  log "pipe 3"
+  unzip `pipe` sOut
+
+  writeString sIn UTF8 testString do
+    end sIn do
+      onDataString sOut UTF8 \str -> do
+        assertEqual str testString
+
+foreign import data GZIP :: !
+
+foreign import createGzip :: forall eff. Eff (gzip :: GZIP | eff) (Duplex (gzip :: GZIP | eff))
+foreign import createGunzip :: forall eff. Eff (gzip :: GZIP | eff) (Duplex (gzip :: GZIP | eff))
+
+foreign import data PASS_THROUGH :: !
+
+-- | Create a PassThrough stream, which simply writes its input to its output.
+foreign import passThrough :: forall eff. Eff (stream :: PASS_THROUGH | eff) (Duplex (stream :: PASS_THROUGH | eff))