migrated casper/alert tests to new testing format

 /*global casper*/
 /*jshint strict:false*/
-
-var ok = false;
-
-casper.on('remote.alert', function(message) {
-    ok = message === 'plop';
-});
-
-casper.start('tests/site/alert.html').run(function() {
-    this.test.assert(ok, 'alert event has been intercepted');
-    this.removeAllListeners('remote.alert');
-    this.test.done(1);
+casper.test.begin('alert events', 1, function(test) {
+    var ok = false;
+    casper.on('remote.alert', function(message) {
+        ok = message === 'plop';
+    });
+    casper.start('tests/site/alert.html').run(function() {
+        this.test.assert(ok, 'alert event has been intercepted');
+        this.removeAllListeners('remote.alert');
+        test.done();
+    });
 });