diff --git a/.travis.yml b/.travis.yml
index 791313a..3a3392d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,6 +2,8 @@ language: node_js
 sudo: false
 node_js:
   - 0.10
+  - 0.12
+  - 4.1
 env:
   - PATH=$HOME/purescript:$PATH
 install:
diff --git a/Gruntfile.js b/Gruntfile.js
deleted file mode 100644
index ed5a3d2..0000000
--- a/Gruntfile.js
+++ /dev/null
@@ -1,30 +0,0 @@
-module.exports = function(grunt) {
-
-  "use strict";
-
-  grunt.initConfig({ 
-  
-    libFiles: [
-      "src/**/*.purs",
-      "bower_components/purescript-*/src/**/*.purs",
-    ],
-    
-    clean: ["output"],
-  
-    pscMake: ["<%=libFiles%>"],
-    dotPsci: ["<%=libFiles%>"],
-    docgen: {
-        readme: {
-            src: "src/**/*.purs",
-            dest: "README.md"
-        }
-    }
-
-  });
-
-  grunt.loadNpmTasks("grunt-contrib-clean");
-  grunt.loadNpmTasks("grunt-purescript");
-  
-  grunt.registerTask("make", ["pscMake", "dotPsci", "docgen"]);
-  grunt.registerTask("default", ["make"]);
-};
diff --git a/bower.json b/bower.json
index 48788e8..18bcf26 100644
--- a/bower.json
+++ b/bower.json
@@ -11,5 +11,10 @@
   "dependencies": {
     "purescript-eff": "~0.1.0",
     "purescript-maybe": "~0.3.1"
+  },
+  "devDependencies": {
+    "purescript-assert": "~0.1.1",
+    "purescript-console": "~0.1.1",
+    "purescript-foldable-traversable": "~0.4.1"
   }
 }
diff --git a/docs/Node/Buffer.md b/docs/Node/Buffer.md
index 4fecedb..5781e37 100644
--- a/docs/Node/Buffer.md
+++ b/docs/Node/Buffer.md
@@ -30,13 +30,13 @@ An instance of Node's Buffer class.
 instance showBuffer :: Show Buffer
 ```
 
-#### `BufferWrite`
+#### `BUFFER`
 
 ``` purescript
-data BufferWrite :: !
+data BUFFER :: !
 ```
 
-Effect for buffer modification.
+Effect for buffer creation, reading, or writing.
 
 #### `BufferValueType`
 
@@ -68,7 +68,7 @@ instance showBufferValueType :: Show BufferValueType
 #### `create`
 
 ``` purescript
-create :: Int -> Buffer
+create :: forall e. Int -> Eff (buffer :: BUFFER | e) Buffer
 ```
 
 Creates a new buffer of the specified size.
@@ -76,7 +76,7 @@ Creates a new buffer of the specified size.
 #### `fromArray`
 
 ``` purescript
-fromArray :: Array Octet -> Buffer
+fromArray :: forall e. Array Octet -> Eff (buffer :: BUFFER | e) Buffer
 ```
 
 Creates a new buffer from an array of octets, sized to match the array.
@@ -84,7 +84,7 @@ Creates a new buffer from an array of octets, sized to match the array.
 #### `fromString`
 
 ``` purescript
-fromString :: String -> Encoding -> Buffer
+fromString :: forall e. String -> Encoding -> Eff (buffer :: BUFFER | e) Buffer
 ```
 
 Creates a new buffer from a string with the specified encoding, sized to
@@ -93,7 +93,7 @@ match the string.
 #### `read`
 
 ``` purescript
-read :: BufferValueType -> Offset -> Buffer -> Int
+read :: forall e. BufferValueType -> Offset -> Buffer -> Eff (buffer :: BUFFER | e) Int
 ```
 
 Reads a numeric value from a buffer at the specified offset.
@@ -101,7 +101,7 @@ Reads a numeric value from a buffer at the specified offset.
 #### `readString`
 
 ``` purescript
-readString :: Encoding -> Offset -> Offset -> Buffer -> String
+readString :: forall e. Encoding -> Offset -> Offset -> Buffer -> Eff (buffer :: BUFFER | e) String
 ```
 
 Reads a section of a buffer as a string with the specified encoding.
@@ -109,7 +109,7 @@ Reads a section of a buffer as a string with the specified encoding.
 #### `toString`
 
 ``` purescript
-toString :: Encoding -> Buffer -> String
+toString :: forall e. Encoding -> Buffer -> Eff (buffer :: BUFFER | e) String
 ```
 
 Reads the buffer as a string with the specified encoding.
@@ -117,7 +117,7 @@ Reads the buffer as a string with the specified encoding.
 #### `write`
 
 ``` purescript
-write :: forall e. BufferValueType -> Int -> Offset -> Buffer -> Eff (buffer :: BufferWrite | e) Unit
+write :: forall e. BufferValueType -> Int -> Offset -> Buffer -> Eff (buffer :: BUFFER | e) Unit
 ```
 
 Writes a numeric value to a buffer at the specified offset.
@@ -125,7 +125,7 @@ Writes a numeric value to a buffer at the specified offset.
 #### `writeString`
 
 ``` purescript
-writeString :: forall e. Encoding -> Offset -> Int -> String -> Buffer -> Eff (buffer :: BufferWrite | e) Int
+writeString :: forall e. Encoding -> Offset -> Int -> String -> Buffer -> Eff (buffer :: BUFFER | e) Int
 ```
 
 Writes octets from a string to a buffer at the specified offset. Multi-byte
@@ -135,7 +135,7 @@ to write them fully. The number of bytes written is returned.
 #### `toArray`
 
 ``` purescript
-toArray :: Buffer -> Array Octet
+toArray :: forall e. Buffer -> Eff (buffer :: BUFFER | e) (Array Octet)
 ```
 
 Creates an array of octets from a buffer's contents.
@@ -143,7 +143,7 @@ Creates an array of octets from a buffer's contents.
 #### `getAtOffset`
 
 ``` purescript
-getAtOffset :: Offset -> Buffer -> Maybe Octet
+getAtOffset :: forall e. Offset -> Buffer -> Eff (buffer :: BUFFER | e) (Maybe Octet)
 ```
 
 Reads an octet from a buffer at the specified offset.
@@ -151,7 +151,7 @@ Reads an octet from a buffer at the specified offset.
 #### `setAtOffset`
 
 ``` purescript
-setAtOffset :: forall e. Octet -> Offset -> Buffer -> Eff (buffer :: BufferWrite | e) Unit
+setAtOffset :: forall e. Octet -> Offset -> Buffer -> Eff (buffer :: BUFFER | e) Unit
 ```
 
 Writes an octet in the buffer at the specified offset.
@@ -159,7 +159,7 @@ Writes an octet in the buffer at the specified offset.
 #### `size`
 
 ``` purescript
-size :: Buffer -> Int
+size :: forall e. Buffer -> Eff (buffer :: BUFFER | e) Int
 ```
 
 Returns the size of a buffer.
@@ -167,7 +167,7 @@ Returns the size of a buffer.
 #### `concat`
 
 ``` purescript
-concat :: Array Buffer -> Buffer
+concat :: forall e. Array Buffer -> Eff (buffer :: BUFFER | e) Buffer
 ```
 
 Concatenates a list of buffers.
@@ -175,7 +175,7 @@ Concatenates a list of buffers.
 #### `concat'`
 
 ``` purescript
-concat' :: Array Buffer -> Int -> Buffer
+concat' :: forall e. Array Buffer -> Int -> Eff (buffer :: BUFFER | e) Buffer
 ```
 
 Concatenates a list of buffers, combining them into a new buffer of the
@@ -184,16 +184,16 @@ specified length.
 #### `copy`
 
 ``` purescript
-copy :: Offset -> Offset -> Buffer -> Offset -> Buffer -> Buffer
+copy :: forall e. Offset -> Offset -> Buffer -> Offset -> Buffer -> Eff (buffer :: BUFFER | e) Int
 ```
 
 Copies a section of a source buffer into a target buffer at the specified
-offset.
+offset, and returns the number of octets copied.
 
 #### `fill`
 
 ``` purescript
-fill :: forall e. Octet -> Offset -> Offset -> Buffer -> Eff (buffer :: BufferWrite | e) Unit
+fill :: forall e. Octet -> Offset -> Offset -> Buffer -> Eff (buffer :: BUFFER | e) Unit
 ```
 
 Fills a range in a buffer with the specified octet.
diff --git a/src/Node/Buffer.js b/src/Node/Buffer.js
index c625266..88b4754 100644
--- a/src/Node/Buffer.js
+++ b/src/Node/Buffer.js
@@ -8,23 +8,31 @@
 exports.showImpl = require('util').inspect;
 
 exports.create = function (size) {
-  return new Buffer(size);
+  return function() {
+    return new Buffer(size);
+  };
 };
 
 exports.fromArray = function (octets) {
-  return new Buffer(octets);
+  return function() {
+    return new Buffer(octets);
+  };
 };
 
 exports.fromStringImpl = function (str) {
   return function (encoding) {
-    return new Buffer(str, encoding);
+    return function() {
+      return new Buffer(str, encoding);
+    };
   };
 };
 
 exports.readImpl = function (ty) {
   return function (offset) {
     return function (buf) {
-      return buf['read' + ty](offset);
+      return function() {
+        return buf['read' + ty](offset);
+      };
     };
   };
 };
@@ -33,7 +41,9 @@ exports.readStringImpl = function (enc) {
   return function (start) {
     return function (end) {
       return function (buff) {
-        return buff.toString(enc, start, end);
+        return function() {
+          return buff.toString(enc, start, end);
+        };
       };
     };
   };
@@ -41,7 +51,9 @@ exports.readStringImpl = function (enc) {
 
 exports.toStringImpl = function (enc) {
   return function (buff) {
-    return buff.toString(enc);
+    return function() {
+      return buff.toString(enc);
+    };
   };
 };
 
@@ -73,16 +85,21 @@ exports.writeStringImpl = function (enc) {
 };
 
 exports.toArray = function (buff) {
-  return buff.toJSON();
+  return function() {
+    var json = buff.toJSON()
+    return json.data || json;
+  };
 };
 
 exports.getAtOffsetImpl = function (nothing) {
   return function (just) {
     return function (buff) {
       return function (offset) {
-        var octet = buff[offset];
-        return octet == null ? nothing
-                             : just(buff[i]);
+        return function() {
+          var octet = buff[offset];
+          return octet == null ? nothing
+                               : just(buff[i]);
+        };
       };
     };
   };
@@ -91,25 +108,33 @@ exports.getAtOffsetImpl = function (nothing) {
 exports.setAtOffset = function (value) {
   return function (offset) {
     return function (buff) {
-      buff[offset] = value;
-      return {};
+      return function() {
+        buff[offset] = value;
+        return {};
+      };
     };
   };
 };
 
 exports.size = function (buff) {
-  return buff.length;
+  return function() {
+    return buff.length;
+  };
 };
 
 
 
 exports.concat = function (buffs) {
-  return Buffer.concat(buffs);
+  return function() {
+    return Buffer.concat(buffs);
+  };
 };
 
-exports.concat$prime = function (buffs) {
+exports["concat'"] = function (buffs) {
   return function (totalLength) {
-    return Buffer.concat(buffs, totalLength);
+    return function() {
+      return Buffer.concat(buffs, totalLength);
+    };
   };
 };
 
@@ -118,21 +143,23 @@ exports.copy = function (srcStart) {
     return function (src) {
       return function (targStart) {
         return function (targ) {
-          return src.copy(targ, targStart, srcStart, strcEnd);
+          return function() {
+            return src.copy(targ, targStart, srcStart, srcEnd);
+          };
         };
       };
     };
   };
 };
 
-exports.fill = function (buff) {
-  return function (octet) {
-    return function (start) {
-      return function (end) {
+exports.fill = function (octet) {
+  return function (start) {
+    return function (end) {
+      return function (buf) {
         return function() {
-          buff.fill(octet, start, end);
+          buf.fill(octet, start, end);
           return {};
-        }
+        };
       };
     };
   };
diff --git a/src/Node/Buffer.purs b/src/Node/Buffer.purs
index abb7a34..891a31e 100644
--- a/src/Node/Buffer.purs
+++ b/src/Node/Buffer.purs
@@ -2,7 +2,7 @@ module Node.Buffer
   ( Octet()
   , Offset()
   , Buffer()
-  , BufferWrite()
+  , BUFFER()
   , BufferValueType(..)
   , create
   , fromArray
@@ -42,8 +42,8 @@ instance showBuffer :: Show Buffer where
 
 foreign import showImpl :: Buffer -> String
 
--- | Effect for buffer modification.
-foreign import data BufferWrite :: !
+-- | Effect for buffer creation, reading, or writing.
+foreign import data BUFFER :: !
 
 -- | Enumeration of the numeric types that can be written to a buffer.
 data BufferValueType
@@ -79,80 +79,81 @@ instance showBufferValueType :: Show BufferValueType where
   show DoubleBE = "DoubleBE"
 
 -- | Creates a new buffer of the specified size.
-foreign import create :: Int -> Buffer
+foreign import create :: forall e. Int -> Eff (buffer :: BUFFER | e) Buffer
 
 -- | Creates a new buffer from an array of octets, sized to match the array.
-foreign import fromArray :: Array Octet -> Buffer
+foreign import fromArray :: forall e. Array Octet -> Eff (buffer :: BUFFER | e) Buffer
 
 -- | Creates a new buffer from a string with the specified encoding, sized to
 -- | match the string.
-fromString :: String -> Encoding -> Buffer
+fromString :: forall e. String -> Encoding -> Eff (buffer :: BUFFER | e) Buffer
 fromString str = fromStringImpl str <<< show
 
-foreign import fromStringImpl :: String -> String -> Buffer
+foreign import fromStringImpl :: forall e. String -> String -> Eff (buffer :: BUFFER | e) Buffer
 
 -- | Reads a numeric value from a buffer at the specified offset.
-read :: BufferValueType -> Offset -> Buffer -> Int
+read :: forall e. BufferValueType -> Offset -> Buffer -> Eff (buffer :: BUFFER | e) Int
 read = readImpl <<< show
 
-foreign import readImpl :: String -> Offset -> Buffer -> Int
+foreign import readImpl :: forall e. String -> Offset -> Buffer -> Eff (buffer :: BUFFER | e) Int
 
 -- | Reads a section of a buffer as a string with the specified encoding.
-readString :: Encoding -> Offset -> Offset -> Buffer -> String
+readString :: forall e. Encoding -> Offset -> Offset -> Buffer -> Eff (buffer :: BUFFER | e) String
 readString = readStringImpl <<< show
 
-foreign import readStringImpl :: String -> Offset -> Offset -> Buffer -> String
+foreign import readStringImpl ::
+  forall e. String -> Offset -> Offset -> Buffer -> Eff (buffer :: BUFFER | e) String
 
 -- | Reads the buffer as a string with the specified encoding.
-toString :: Encoding -> Buffer -> String
+toString :: forall e. Encoding -> Buffer -> Eff (buffer :: BUFFER | e) String
 toString = toStringImpl <<< show
 
-foreign import toStringImpl :: String -> Buffer -> String
+foreign import toStringImpl :: forall e. String -> Buffer -> Eff (buffer :: BUFFER | e) String
 
 -- | Writes a numeric value to a buffer at the specified offset.
-write :: forall e. BufferValueType -> Int -> Offset -> Buffer -> Eff (buffer :: BufferWrite | e) Unit
+write :: forall e. BufferValueType -> Int -> Offset -> Buffer -> Eff (buffer :: BUFFER | e) Unit
 write = writeImpl <<< show
 
 foreign import writeImpl ::
-  forall e. String -> Int -> Offset -> Buffer -> Eff (buffer :: BufferWrite | e) Unit
+  forall e. String -> Int -> Offset -> Buffer -> Eff (buffer :: BUFFER | e) Unit
 
 -- | Writes octets from a string to a buffer at the specified offset. Multi-byte
 -- | characters will not be written to the buffer if there is not enough capacity
 -- | to write them fully. The number of bytes written is returned.
-writeString :: forall e. Encoding -> Offset -> Int -> String -> Buffer -> Eff (buffer :: BufferWrite | e) Int
+writeString :: forall e. Encoding -> Offset -> Int -> String -> Buffer -> Eff (buffer :: BUFFER | e) Int
 writeString = writeStringImpl <<< show
 
 foreign import writeStringImpl ::
-  forall e. String -> Offset -> Int -> String -> Buffer -> Eff (buffer :: BufferWrite | e) Int
+  forall e. String -> Offset -> Int -> String -> Buffer -> Eff (buffer :: BUFFER | e) Int
 
 -- | Creates an array of octets from a buffer's contents.
-foreign import toArray :: Buffer -> Array Octet
+foreign import toArray :: forall e. Buffer -> Eff (buffer :: BUFFER | e) (Array Octet)
 
 -- | Reads an octet from a buffer at the specified offset.
-getAtOffset :: Offset -> Buffer -> Maybe Octet
+getAtOffset :: forall e. Offset -> Buffer -> Eff (buffer :: BUFFER | e) (Maybe Octet)
 getAtOffset = getAtOffsetImpl Just Nothing
 
 foreign import getAtOffsetImpl ::
-  (Octet -> Maybe Octet) -> Maybe Octet -> Offset -> Buffer -> Maybe Octet
+  forall e. (Octet -> Maybe Octet) -> Maybe Octet -> Offset -> Buffer -> Eff (buffer :: BUFFER | e) (Maybe Octet)
 
 -- | Writes an octet in the buffer at the specified offset.
 foreign import setAtOffset ::
-  forall e. Octet -> Offset -> Buffer -> Eff (buffer :: BufferWrite | e) Unit
+  forall e. Octet -> Offset -> Buffer -> Eff (buffer :: BUFFER | e) Unit
 
 -- | Returns the size of a buffer.
-foreign import size :: Buffer -> Int
+foreign import size :: forall e. Buffer -> Eff (buffer :: BUFFER | e) Int
 
 -- | Concatenates a list of buffers.
-foreign import concat :: Array Buffer -> Buffer
+foreign import concat :: forall e. Array Buffer -> Eff (buffer :: BUFFER | e) Buffer
 
 -- | Concatenates a list of buffers, combining them into a new buffer of the
 -- | specified length.
-foreign import concat' :: Array Buffer -> Int -> Buffer
+foreign import concat' :: forall e. Array Buffer -> Int -> Eff (buffer :: BUFFER | e) Buffer
 
 -- | Copies a section of a source buffer into a target buffer at the specified
--- | offset.
-foreign import copy :: Offset -> Offset -> Buffer -> Offset -> Buffer -> Buffer
+-- | offset, and returns the number of octets copied.
+foreign import copy :: forall e. Offset -> Offset -> Buffer -> Offset -> Buffer -> Eff (buffer :: BUFFER | e) Int
 
 -- | Fills a range in a buffer with the specified octet.
 foreign import fill ::
-  forall e. Octet -> Offset -> Offset -> Buffer -> Eff (buffer :: BufferWrite | e) Unit
+  forall e. Octet -> Offset -> Offset -> Buffer -> Eff (buffer :: BUFFER | e) Unit
diff --git a/test/Main.purs b/test/Main.purs
index 588aecb..7b5cbe6 100644
--- a/test/Main.purs
+++ b/test/Main.purs
@@ -1,8 +1,129 @@
 module Test.Main where
 
 import Prelude
+import Data.Traversable (traverse)
 import Control.Monad.Eff
+import Control.Monad.Eff.Console (log, CONSOLE())
+import Test.Assert
 
--- TODO
-main :: forall e. Eff e Unit
-main = return unit
+import Node.Buffer
+import Node.Encoding
+
+type Test = forall e. Eff (assert :: ASSERT, buffer :: BUFFER, console :: CONSOLE | e) Unit
+
+main :: Test
+main = do
+  log "Testing..."
+
+  log "Reading and writing"
+  testReadWrite
+
+  log "fromArray"
+  testFromArray
+
+  log "toArray"
+  testToArray
+
+  log "fromString"
+  testFromString
+
+  log "toString"
+  testToString
+
+  log "readString"
+  testReadString
+
+  log "copy"
+  testCopy
+
+  log "fill"
+  testFill
+
+  log "concat'"
+  testConcat'
+
+testReadWrite :: Test
+testReadWrite = do
+  buf <- create 1
+  let val = 42
+  write UInt8 val 0 buf
+  readVal <- read UInt8 0 buf
+
+  assertEq val readVal
+
+testFromArray :: Test
+testFromArray = do
+  buf <- fromArray [1,2,3,4,5]
+  readVal <- read UInt8 2 buf
+
+  assertEq 3 readVal
+
+testToArray :: Test
+testToArray = do
+  let val = [1,2,67,3,3,7,8,3,4,237]
+
+  buf    <- fromArray val
+  valOut <- toArray buf
+
+  assertEq val valOut
+
+testFromString :: Test
+testFromString = do
+  let str = "hello, world"
+
+  buf <- fromString str ASCII
+  val <- read UInt8 6 buf
+
+  assertEq val 32 -- ASCII space
+
+testToString :: Test
+testToString = do
+  let str = "hello, world"
+
+  buf    <- fromString str ASCII
+  strOut <- toString ASCII buf
+
+  assertEq str strOut
+
+testReadString :: Test
+testReadString = do
+  let str = "hello, world"
+
+  buf    <- fromString str ASCII
+  strOut <- readString ASCII 7 12 buf
+
+  assertEq "world" strOut
+
+testCopy :: Test
+testCopy = do
+  buf1 <- fromArray [1,2,3,4,5]
+  buf2 <- fromArray [10,9,8,7,6]
+
+  copied <- copy 0 3 buf1 2 buf2
+  out    <- toArray buf2
+
+  assertEq copied 3
+  assertEq out [10,9,1,2,3]
+
+testFill :: Test
+testFill = do
+  buf <- fromArray [1,1,1,1,1]
+  fill 42 2 4 buf
+  out <- toArray buf
+
+  assertEq [1,1,42,42,1] out
+
+testConcat' :: Test
+testConcat' = do
+  bufs <- traverse fromArray $ map (\x -> [x, x+1, x+2]) [0,3,6,9,12]
+  buf  <- concat' bufs 15
+  out  <- toArray buf
+
+  assertEq [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14] out
+
+assertEq :: forall a. (Eq a, Show a) => a -> a -> Test
+assertEq x y =
+  if x == y
+    then return unit
+    else let msg = show x ++ " and " ++ show y ++ " were not equal."
+         in assert' msg false