public void FileExistsGood(string id)
        {
            IDBManager fakeDatabase = new FakeDBManager();

            fakeDatabase.AddFile(file);
            Assert.AreEqual(true, fakeDatabase.FileExists(id));
        }
        public void AddFileGood()
        {
            IDBManager fakeDatabase = new FakeDBManager();

            fakeDatabase.AddFile(file);
            Assert.AreEqual(true, fakeDatabase.FileExists(file.Id));
        }
        public void FileExistsBadNull(string id)
        {
            IDBManager fakeDatabase = new FakeDBManager();

            Assert.Throws <ArgumentNullException>(() =>
            {
                fakeDatabase.FileExists(id);
            }
                                                  );
        }
        public void AddFileBadEmptyString(string id, string name, string extension)
        {
            Mock <Files> fileDouble2 = new Mock <Files>();

            fileDouble2.Setup(file => file.Id).Returns(id);
            fileDouble2.Setup(file => file.Name).Returns(name);
            fileDouble2.Setup(file => file.Extension).Returns(extension);

            file = fileDouble2.Object;

            IDBManager fakeDatabase = new FakeDBManager();

            fakeDatabase.AddFile(file);


            Assert.AreEqual(false, fakeDatabase.FileExists(file.Id));
        }
        public void FileDoesntExists(string id)
        {
            FakeDBManager fakeDatabase = new FakeDBManager();

            Assert.AreEqual(false, fakeDatabase.FileExists(id));
        }