adding toFormData test

test/specs/helpers/toFormData.spec.js

+var toFormData = require("../../../lib/helpers/toFormData");
+
+describe("toFormData", function () {
+  it("Convert nested data object to FormDAta", function () {
+    var o = {
+      val: 123,
+      nested: {
+        arr: ["hello", "world"],
+      },
+    };
+
+    convertedVal = toFormData(o);
+    expect(convertedVal instanceof FormData).toEqual(true);
+    expect(Array.from(convertedVal.keys()).length).toEqual(3);
+    expect(convertedVal.get("val")).toEqual("123")
+    expect(convertedVal.get("nested.arr.0")).toEqual("hello")
+  });
+});