add role tests

tests/helpers/roles/getRoles.ts

@@ -0,0 +1,9 @@
+import { Bot } from "../../../src/bot.ts";
+import { Cache } from "../../../src/cache.ts";
+import { assertEquals, assertExists } from "../../deps.ts";
+
+export async function getRolesTest(bot: Bot<Cache>, guildId: bigint, t: Deno.TestContext) {
+  const roles = await bot.helpers.getRoles(guildId);
+
+  assertEquals(bot.cache.guilds.get(guildId)?.roles.size, roles.length);
+}