test callback error handling

lib/index.js

@@ -44,10 +44,10 @@ ChainGang.prototype.shift = function() {
     };
   }
 };
-ChainGang.prototype.finish = function(name) {
+ChainGang.prototype.finish = function(name, err) {
   delete this.index[name];
-  this.emit(name);
-  return this.emit('finished', name);
+  this.emit(name, err);
+  return this.emit('finished', name, err);
 };
 ChainGang.prototype.emit = function(event) {
   var args;
@@ -101,13 +101,13 @@ Worker.prototype.perform = function() {
   try {
     return data.callback(this);
   } catch (err) {
-    sys.puts(sys.inspect(err));
-    this.chain.emit('error', err, data.name);
-    return finish(data.name);
+    this.chain.emit(("error-" + data.name), err);
+    this.chain.emit("error", err, data.name);
+    return this.finish(data.name, err);
   }
 };
-Worker.prototype.finish = function() {
-  this.chain.finish(this.performing);
+Worker.prototype.finish = function(err) {
+  this.chain.finish(this.performing, err);
   this.performing = false;
   return this.perform();
 };

src/index.coffee

@@ -31,12 +31,14 @@ class ChainGang
   # Emits ('add', name)
   add: (task, name, callback) ->
     name: or @default_name_for task
+
     if callback then @events.addListener name, callback
     if @index[name] != undefined then return
 
     @queue.push name
     @index[name]: task
     @events.emit 'add', name
+
     if @active then @perform()
 
   # Public: Attempts to find an idle worker to perform a job.
@@ -63,12 +65,12 @@ class ChainGang
   # name - The unique String job identifier.
   #
   # Returns nothing.
-  # Emits (name)
-  # Emits ('finished', name)
-  finish: (name) ->
+  # Emits (name, err)
+  # Emits ('finished', name, err)
+  finish: (name, err) ->
     delete @index[name]
-    @emit name
-    @emit 'finished', name
+    @emit name, err
+    @emit 'finished', name, err
 
   emit: (event, args...) ->
     @events.emit event, args...
@@ -118,15 +120,15 @@ class Worker
     try
       data.callback this
     catch err
-      sys.puts sys.inspect(err)
-      @chain.emit 'error', err, data.name
-      finish data.name
+      @chain.emit "error-$data.name", err
+      @chain.emit "error", err, data.name
+      @finish data.name, err
 
   # Finishes the current job, and looks for another.
   #
   # Returns nothing.
-  finish: ->
-    @chain.finish @performing
+  finish: (err) ->
+    @chain.finish @performing, err
     @performing: false
     @perform()
 

test/error_test.coffee

@@ -0,0 +1,39 @@
+sys:       require('sys')
+assert:    require('assert')
+chainGang: require('../src')
+
+chain: chainGang.create({workers: 2})
+assert.equal(2, chain.workers.length)
+
+called_finished: false
+called_named: false
+called_error: false
+called_custom_error: false
+
+chain.addListener 'finished', (name, err) ->
+  assert.ok err
+  assert.equal 'foo', name
+  called_finished: true
+
+chain.addListener 'foo', (err) ->
+  assert.ok err
+  called_named: true
+
+chain.addListener 'error', (err, name) ->
+  assert.ok err
+  assert.equal 'foo', name
+  called_error: true
+
+chain.addListener 'error-foo', (err) ->
+  assert.ok err
+  called_custom_error: true
+
+chain.add ->
+  a.b == c
+, 'foo'
+
+process.addListener 'exit', ->
+  assert.ok called_error
+  assert.ok called_custom_error
+  assert.ok called_finished
+  assert.ok called_named