private static async Task<SolutionService> GetSolutionServiceAsync(Solution solution, Dictionary<Checksum, object> map = null)
{
// make sure checksum is calculated
await solution.State.GetChecksumAsync(CancellationToken.None);
map = map ?? new Dictionary<Checksum, object>();
solution.AppendAssetMap(map);
var sessionId = 0;
var storage = new AssetStorage();
var source = new TestAssetSource(storage, sessionId, map);
var service = new SolutionService(new AssetService(sessionId, storage));
return service;
}