Do not include main map during submap testing

code/__defines/_compile_options.dm

@@ -5,4 +5,10 @@
 								0 to allow using external resources or on-demand behaviour;
 								1 to use the default behaviour (preload compiled in recourses, not player uploaded ones);
 								2 for preloading absolutely everything;
-								*/
+								*/
+
+// If we are doing the map test build, do not include the main maps, only the submaps.
+#if MAP_TEST
+	#define USING_MAP_DATUM /datum/map
+	#define MAP_OVERRIDE 1
+#endif