public void AsString()
        {
            Assert.AreEqual(string.Empty, subject.ToString());

            subject.Append("Unity");
            Assert.AreEqual("Unity", subject.ToString());

            subject.Append("Adrenalyn", "1.1.1");
            Assert.AreEqual("Unity Adrenalyn/1.1.1", subject.ToString());

            subject.Append("Foo", "3", "Only Testing");
            Assert.AreEqual("Unity Adrenalyn/1.1.1 Foo/3 (Only Testing)", subject.ToString());

            subject.Append("Bar", comment: "Without Version");
            Assert.AreEqual("Unity Adrenalyn/1.1.1 Foo/3 (Only Testing) Bar (Without Version)", subject.ToString());
        }
        public void RealWorldExample()
        {
            UserAgentBuilder uab = new UserAgentBuilder("Unity", "2.1.0", "iOS")
                                   .Append("Unity", "5.2.3")
                                   .Append("mobile_hires");

            Assert.AreEqual("Unity/2.1.0 (iOS) Unity/5.2.3 mobile_hires", uab.ToString());
        }