private void VerifyFlag(Func <TestData.FlagBuilder, TestData.FlagBuilder> configureFlag, string expectedProps)
{
var expectedJson = "{\"key\":\"flagkey\",\"version\":1," + expectedProps +
",\"clientSide\":false,\"deleted\":false,\"prerequisites\":[],\"salt\":\"\"}";
var td = TestData.DataSource();
td.CreateDataSource(_context, _updates).Start();
td.Update(configureFlag(_td.Flag("flagkey")));
Assert.Equal(1, _updates.Upserts.Count);
var up = _updates.Upserts.Take();
var json = LdValue.Parse(DataModel.Features.Serialize(up.Item));
AssertHelpers.JsonEqual(LdValue.Parse(expectedJson), json);
}