know yourself, know your areas (#12078)

tgstation/tgstation#71295

code/game/turfs/turf.dm

@@ -84,6 +84,13 @@ CREATION_TEST_IGNORE_SELF(/turf)
 	///Can this floor be an underlay, for turf damage
 	var/can_underlay = TRUE
 
+#if defined(UNIT_TESTS) || defined(SPACEMAN_DMM)
+	/// For the area_contents list unit test
+	/// Allows us to know our area without needing to preassign it
+	/// Sorry for the mess
+	var/area/in_contents_of
+#endif
+
 /turf/vv_edit_var(var_name, new_value)
 	var/static/list/banned_edits = list("x", "y", "z")
 	if(var_name in banned_edits)

code/modules/unit_tests/area_contents.dm

@@ -4,28 +4,26 @@
 	priority = TEST_LONGER
 
 /datum/unit_test/area_contents/Run()
-	/// assoc list of turfs -> areas
-	var/list/turf_to_area = list()
 	// First, we check that there are no entries in more then one area
 	// That or duplicate entries
 	for(var/area/space in GLOB.areas)
 		for(var/turf/position as anything in space.get_contained_turfs())
 			if(!isturf(position))
 				TEST_FAIL("Found a [position.type] in [space.type]'s turf listing")
 
-			var/area/existing = turf_to_area[position]
-			if(existing == space)
-				TEST_FAIL("Found a duplicate turf [position.type] inside [space.type]'s turf listing")
-			else if(existing)
-				TEST_FAIL("Found a shared turf [position.type] between [space.type] and [existing.type]'s turf listings")
+			if(position.in_contents_of)
+				var/area/existing = position.in_contents_of
+				if(existing == space)
+					TEST_FAIL("Found a duplicate turf [position.type] inside [space.type]'s turf listing")
+				else
+					TEST_FAIL("Found a shared turf [position.type] between [space.type] and [existing.type]'s turf listings")
 
 			var/area/dream_spot = position.loc
 			if(dream_spot != space)
 				TEST_FAIL("Found a turf [position.type] which is IN [dream_spot.type], but is registered as being in [space.type]")
 
-			turf_to_area[position] = space
+			position.in_contents_of = space
 
 	for(var/turf/position in ALL_TURFS())
-		if(!turf_to_area[position])
+		if(!position.in_contents_of)
 			TEST_FAIL("Found a turf [position.type] inside [position.loc.type] that is NOT stored in any area's turf listing")
-