public void DeletesUnlistedVersion(string version)
            {
                var unlisted = new FilteredVersionProperties(version, listed: false);

                _list.Upsert(unlisted);

                var output = _list.Delete(unlisted.ParsedVersion);

                Assert.Equal(SearchIndexChangeType.UpdateVersionList, output.Search);
                Assert.Equal(
                    new[]
                {
                    HijackIndexChange.Delete(unlisted.ParsedVersion),
                    HijackIndexChange.SetLatestToTrue(InitialParsedVersion),
                },
                    output.Hijack.ToArray());
                Assert.Equal(InitialFullVersion, _list.GetLatestVersionInfo().FullVersion);
                Assert.Equal(InitialParsedVersion, _list._latestOrNull);
                Assert.Equal(new[] { InitialFullVersion }, _list.GetLatestVersionInfo().ListedFullVersions);
                Assert.Equal(new[] { InitialParsedVersion }, _list._versions.Keys.ToArray());
            }