fix through/through-tests.ts

through/through-tests.ts

@@ -1,3 +1,5 @@
+/// <reference path="./through.d.ts" />
+
 import through = require('through');
 
 var i = 0;
@@ -6,4 +8,4 @@ through(
 		this.queue((i++).toString());
 	}, function () {
 		this.queue(null);
-	}, { autoDestroy: true }).pipe(process.stdout);
+	}, { autoDestroy: true }).pipe(process.stdout);