Add test for setImmediate and process.nextTick.

spec/node/message_loop.coffee

@@ -0,0 +1,20 @@
+assert = require 'assert'
+
+describe 'message loop', ->
+  describe 'process.nextTick', ->
+    it 'should emit the callback', (done) ->
+      process.nextTick done
+
+    it 'should work in nested calls', (done) ->
+      process.nextTick ->
+        process.nextTick ->
+          process.nextTick done
+
+  describe 'setImmediate', ->
+    it 'should emit the callback', (done) ->
+      setImmediate done
+
+    it 'should work in nested calls', (done) ->
+      setImmediate ->
+        setImmediate ->
+          setImmediate done