MongoDB.GridFS.GridFileInfoTest.TestOpenNonExistentFails C# (CSharp) Метод

        public void TestOpenNonExistentFails()
        {
            string filename = "gfi-opennothere.txt";
            GridFile gf = new GridFile(db["tests"], "gfopen");
            GridFileInfo gfi = new GridFileInfo(db["tests"], "gfopen", filename);
            bool thrown = false;
            try{
                GridFileStream gfs = gfi.OpenRead();
            }catch(DirectoryNotFoundException dnfe){
                Assert.AreEqual(gf.Name + Path.VolumeSeparatorChar + filename, dnfe.Message);
                thrown = true;
            }
            Assert.IsTrue(thrown);
        }