Add ability to check chatlog for test assertions. (#27727)

code/tests/_game_test.dm

@@ -1,3 +1,5 @@
+GLOBAL_LIST_EMPTY(game_test_chats)
+
 /// For advanced cases, fail unconditionally but don't return (so a test can return multiple results)
 #define TEST_FAIL(reason) (Fail(reason || "No reason", __FILE__, __LINE__))
 

code/tests/_game_test_puppeteer.dm

@@ -66,3 +66,10 @@
 
 /datum/test_puppeteer/proc/rejuvenate()
 	puppet.rejuvenate()
+
+/datum/test_puppeteer/proc/last_chatlog_has_text(snippet)
+	if(!(puppet.mind.key in GLOB.game_test_chats))
+		return FALSE
+	var/list/puppet_chat_list = GLOB.game_test_chats[puppet.mind.key]
+	var/last_chat_html = puppet_chat_list[length(puppet_chat_list)]
+	return findtextEx(last_chat_html, snippet)

code/tests/attack_chain/test_attack_chain_vehicles.dm

@@ -6,10 +6,9 @@
 	player.click_on(janicart)
 	TEST_ASSERT_EQUAL(janicart.inserted_key, janicart_key, "did not find janicart key in vehicle")
 
-	var/move_delay = janicart.vehicle_move_delay
 	player.spawn_obj_in_hand(/obj/item/borg/upgrade/vtec)
 	player.click_on(janicart)
-	TEST_ASSERT(janicart.vehicle_move_delay < move_delay, "VTEC upgrade not applied properly")
+	TEST_ASSERT(player.last_chatlog_has_text("You upgrade the janicart"), "VTEC upgrade not applied properly")
 
 	TEST_ASSERT_NULL(janicart.mybag, "unexpected trash bag on janicart")
 	var/obj/item/storage/bag/trash/bag = player.spawn_obj_in_hand(/obj/item/storage/bag/trash)