exit when trying to use .test in a non-test env

@@ -157,8 +157,7 @@ var Casper = function Casper(options) {
     this._test = undefined;
     this.__defineGetter__('test', function() {
         if (!phantom.casperTest) {
-            this.emit('tester.called');
-            return;
+            this.die('casper.test property is only available using the `casperjs test` command');
         }
         if (!utils.isObject(this._test)) {
             this._test = tester.create(this);
@@ -166,10 +165,6 @@ var Casper = function Casper(options) {
         return this._test;
     });
 
-    this.once('tester.called', function() {
-        this.warn('please use `casperjs test` command');
-    });
-
     // init phantomjs error handler
     this.initErrorHandler();