Added test

nprogress/NProgress-tests.ts

@@ -3,6 +3,7 @@
 function test_basics() {
     NProgress.start();
     NProgress.inc();
+    NProgress.inc(0.2);
     NProgress.done();
     NProgress.set(0.5);
 
@@ -29,4 +30,4 @@ function test_configuration() {
         trickleRate: 0.42,
         trickleSpeed: 42
     });
-}
+}