Perhaps some values from UnitTestHelpers can be replaced by those in Game.LambdaHack.Common.Kind and surely some in other tests can be replaced by those in UnitTestHelpers, because in some cases they are identical.

If there is a benefit in the stub game arena elements being different in test files than in UnitTestHelpers, perhaps the extra ones should be moved to UnitTestHelpers, as well, and perhaps different blocks of tests in the same file could use different such elements, not just one.