public void BuildTest2()
        {
            ExtensionFilter ef = ExtensionFilter.Build("docx?");

            Assert.IsTrue(ef.Accepts("test.doc"));
            Assert.IsTrue(ef.Accepts("test.docx"));
            Assert.IsFalse(ef.Accepts("test.mkv"));
        }
        public void BuildTest1()
        {
            ExtensionFilter ef = ExtensionFilter.Build(new List <string>()
            {
                "txt", "doc", "avi"
            });

            Assert.IsTrue(ef.Accepts("test.txt"));
            Assert.IsTrue(ef.Accepts("test.doc"));
            Assert.IsFalse(ef.Accepts("test.mkv"));
        }