describe("Count", function () {
    it("all", function () {
        expect(Users.Count()).toBe(16);
    });

    it("age > 80", function () {
        expect(Users.Count(x => x.Age > 80)).toBe(2);
    });

    it("age < 18", function () {
        expect(Users.Count(x => x.Age < 18)).toBe(0);
    });
});