public void TestFromJson()
        {
            JString jstring = new JString("*");
            WildcardContainer <string> s = WildcardContainer <string> .FromJson(jstring, u => u.AsString());

            s.Should().BeEmpty();

            jstring = new JString("hello world");
            Action action = () => WildcardContainer <string> .FromJson(jstring, u => u.AsString());

            action.Should().Throw <FormatException>();

            JObject alice = new JObject();

            alice["name"] = "alice";
            alice["age"]  = 30;
            JArray jarray = new JArray {
                alice
            };
            WildcardContainer <string> r = WildcardContainer <string> .FromJson(jarray, u => u.AsString());

            r[0].Should().Be("{\"name\":\"alice\",\"age\":30}");

            JBoolean jbool = new JBoolean();

            action = () => WildcardContainer <string> .FromJson(jbool, u => u.AsString());

            action.Should().Throw <FormatException>();
        }