add a test on string trimming API

tests/testcoreAPI.ts

@@ -0,0 +1,20 @@
+import * as JQuery from "../src/libs/jquery-3.2.1.min";
+import { OS as _OS_ } from "../dist/antos";
+// some global variable
+const _w_ = window as any;
+_w_.$ = JQuery;
+const OS = _OS_ as any;
+_w_.OS = OS;
+
+interface GenericObject<T> {
+    [propName: string]: T;
+}
+
+// test the string trim API
+test("Test string trim", () => {
+    let s = "hhhhhhello worddddddd" as any;
+    expect(s.trimFromLeft("h")).toBe("ello worddddddd");
+    expect(s.trimFromRight("d")).toBe("hhhhhhello wor");
+    let p = "/this/is/the/path/" as any;
+    expect(p.trimBy("/")).toBe("this/is/the/path");
+})