Tests: Implement generic default options reachability test

Tests: remove duplicate TestDeathMountain.py
LttP: Move er_seeds out of Main
OriBF: Fix Mapstone typo

test/Reachability.py

@@ -0,0 +1,32 @@
+import unittest
+from argparse import Namespace
+from BaseClasses import MultiWorld
+from worlds.AutoWorld import AutoWorldRegister, call_all
+
+
+class TestBase(unittest.TestCase):
+    _state_cache = {}
+    gen_steps = ["generate_early", "create_regions", "create_items", "set_rules", "generate_basic", "pre_fill"]
+
+    def testAllStateCanReachEverything(self):
+        for game_name, world_type in AutoWorldRegister.world_types.items():
+            if game_name != "Ori and the Blind Forest":  # TODO: fix Ori Logic
+                with self.subTest("Game", game=game_name):
+
+                    world = MultiWorld(1)
+                    world.game[1] = game_name
+                    world.player_name = {1: "Tester"}
+                    world.set_seed()
+                    args = Namespace()
+                    for name, option in world_type.options.items():
+                        setattr(args, name, {1: option.from_any(option.default)})
+                    world.set_options(args)
+                    world.set_default_common_options()
+                    for step in self.gen_steps:
+                        call_all(world, step)
+                    state = world.get_all_state(False)
+                    for location in world.get_locations():
+                        with self.subTest("Location should be reached", location=location):
+                            if not location.can_reach(state):
+                                print("Bla!")
+                            self.assertTrue(location.can_reach(state))