Adds a unit test that makes sure subsystem flags make sense (#96022)

## About The Pull Request

There's a few of these that conflict, mostly relating to timing. This
conflicting won't actually break anything but it does muddy "what is
this doing" somewhat and it's good to be clear so here we go

## Why It's Good For The Game

Makes the MC very slightly harder to confuse yourself with

code/_globalvars/bitfields.dm

@@ -27,6 +27,18 @@ GLOBAL_LIST_INIT(bitfields, generate_bitfields())
 	var/name = pick(flags)
 	return flags[name]
 
+/// Returns null if no such field exists, a list of all matching flags by name otherwise
+/proc/get_matching_bitflags(var_name, value)
+	var/list/valid_bitflags = get_valid_bitflags(var_name)
+	if(!length(valid_bitflags))
+		return null
+
+	var/list/flags = list()
+	for (var/bit_name in valid_bitflags)
+		if (value & valid_bitflags[bit_name])
+			flags += bit_name
+	return flags
+
 DEFINE_BITFIELD(admin_flags, list(
 	"ADMIN" = R_ADMIN,
 	"AUTOLOGIN" = R_AUTOADMIN,

code/controllers/subsystem/throwing.dm

@@ -5,7 +5,7 @@ SUBSYSTEM_DEF(throwing)
 	name = "Throwing"
 	priority = FIRE_PRIORITY_THROWING
 	wait = 1
-	ss_flags = SS_NO_INIT|SS_KEEP_TIMING|SS_TICKER
+	ss_flags = SS_NO_INIT | SS_TICKER
 	runlevels = RUNLEVEL_GAME | RUNLEVEL_POSTGAME
 
 	var/list/currentrun

code/modules/admin/view_variables/debug_variables.dm

@@ -103,20 +103,14 @@
 		return "<a href='byond://?_src_=vars;[HrefToken()];[link_vars]'>/list ([list_value.len])</a>"
 
 	// if it's a number, is it a bitflag?
-	var/list/valid_bitflags
-	if(!isnum(name))
-		valid_bitflags = get_valid_bitflags(name)
+	var/list/matching_bitflags = get_matching_bitflags(name, value)
 
-	if(!length(valid_bitflags))
-		return "<span class='value'>[VV_HTML_ENCODE(value)]</span>"
+	if(!isnull(matching_bitflags))
+		if(length(matching_bitflags))
+			return "[VV_HTML_ENCODE(matching_bitflags.Join(", "))]"
+		return "NONE"
 
-	var/list/flags = list()
-	for (var/bit_name in valid_bitflags)
-		if (value & valid_bitflags[bit_name])
-			flags += bit_name
-	if(length(flags))
-		return "[VV_HTML_ENCODE(flags.Join(", "))]"
-	return "NONE"
+	return "<span class='value'>[VV_HTML_ENCODE(value)]</span>"
 
 /datum/proc/debug_variable_value(name, level, datum/owner, sanitize, display_flags)
 	if("[src]" != "[type]") // If we have a name var, let's use it.

code/modules/unit_tests/_unit_tests.dm

@@ -327,6 +327,7 @@
 #include "strippable.dm"
 #include "stuns.dm"
 #include "style_hotswapping.dm"
+#include "subsystem_flags.dm"
 #include "subsystem_init.dm"
 #include "suit_sensor.dm"
 #include "suit_storage_icons.dm"

code/modules/unit_tests/subsystem_flags.dm

@@ -0,0 +1,12 @@
+// Ensures subystem flags are set in a coherent way
+/datum/unit_test/subsystem_flags
+
+/datum/unit_test/subsystem_flags/Run()
+	for(var/datum/controller/subsystem/sub_lad as anything in subtypesof(/datum/controller/subsystem))
+		if((sub_lad::ss_flags & (SS_TICKER | SS_KEEP_TIMING)) == (SS_TICKER | SS_KEEP_TIMING))
+			var/list/matching = get_matching_bitflags("ss_flags", sub_lad::ss_flags)
+			TEST_FAIL("[sub_lad] {[matching.Join(" | ")]} had both SS_TICKER and SEE_KEEP_TIMING set, this is redundant! You should likely remove SS_KEEP_TIMING.")
+		if((sub_lad::ss_flags & (SS_POST_FIRE_TIMING | SS_KEEP_TIMING)) == (SS_POST_FIRE_TIMING | SS_KEEP_TIMING))
+			var/list/matching = get_matching_bitflags("ss_flags", sub_lad::ss_flags)
+			TEST_FAIL("[sub_lad] {[matching.Join(" | ")]} had both SS_POST_FIRE_TIMING and SEE_KEEP_TIMING set, this is redundant! You should likely remove SS_KEEP_TIMING as SS_POST_FIRE_TIMING overrides it.")
+