Improve settings tests and validation

settings.js

@@ -32,7 +32,7 @@ const settings = JSON.parse(
 const settings_validations = {
   username: (name) => typeof name === "string",
   password: (pass) => typeof pass === "string" && pass.startsWith("oauth"),
-  channel: (channel) => typeof channel === "string",
+  channel: (channel) => typeof channel === "string" && /^[a-z0-9_]{3,}$/.test(channel), // channel needs to be a valid twitch username (this is used in the chatters URL in twitch.js)
   start_open: (open) => typeof open === "boolean",
   enable_absolute_position: (absolute_position) => typeof absolute_position === "boolean",
   custom_codes_enabled: cc => typeof cc === "boolean",

tests/chat-logs/chat-logs.test.js

@@ -141,6 +141,8 @@ for (const file of testFiles) {
             } else if (command == 'accuracy') {
                 accuracy = parseInt(rest);
             } else if (command == 'settings') {
+                // TODO: ideally new settings would be written to settings.json
+                //       and settings.js could be reloaded instead to validate settings
                 replaceSettings(test.settings, JSON.parse(rest));
             } else if (command == 'chatters') {
                 simSetChatters(JSON.parse(rest));