Added tests for the old version of the definitions

through2/through2-0.4.2-test.ts

@@ -0,0 +1,44 @@
+/// <reference path="./through2-0.4.2.d.ts" />
+/// <reference path="../node/node.d.ts" />
+
+import through2 = require('through2');
+
+var rws: NodeJS.ReadWriteStream;
+
+rws = through2({
+	objectMode: true,
+	allowHalfOpen: true
+}, function (entry: any, enc: string, callback: () => void) {
+	this.push('foo');
+	callback();
+}, () => {
+
+});
+
+rws = through2(function (entry: any, enc: string, callback: () => void) {
+	this.push('foo');
+	callback();
+}, () => {
+
+});
+
+rws = through2(function (entry: any, enc: string, callback: () => void) {
+	this.push('foo');
+	callback();
+});
+
+rws = through2();
+
+// obj
+rws = through2.obj(function (entry: any, enc: string, callback: () => void) {
+	this.push('foo');
+	callback();
+}, () => {
+
+});
+
+rws = through2.obj(function (entry: any, enc: string, callback: () => void) {
+	this.push('foo');
+	callback();
+});
+