So three of them are failing Both ComponentDataWrapper_SetValue_SynchronizesWithEntityManager tests and Initialize_ShouldLogNothing under DefaultWorldInitializationTests I haven't actually looked at tests, but I'm pretty sure just from the error the issue is I don't use the default world initialization and instead use a custom world setup, therefore some systems don't have empty constructors. I think the only solution is probably disabling the DefaultWorld related tests if UNITY_DISABLE_AUTOMATIC_SYSTEM_BOOTSTRAP is set in the project. Not a big deal anyway, just a slight annoyance as I seem to need to include the ecs tests if I want to use ECSTestsFixture in my own tests.