Test all branches of LanguageChangedEvent

src/main/java/app/events/LanguageChangedEvent.java

@@ -17,18 +17,22 @@ public class LanguageChangedEvent extends Event {
   public LanguageChangedEvent(String language) {
     this.language = language;
 
-    switch (language) {
+    switch (language.toLowerCase()) {
 
-      case "Java":
+      case "java":
         Model.setLanguage(new Java());
         break;
 
-      case "Markdown":
+      case "markdown":
         Model.setLanguage(new Markdown());
         break;
 
-      default:
+      case "empty":
+        Model.setLanguage(new Empty());
         break;
+
+      default:
+        throw new IllegalArgumentException("Could not recognize language: " + language);
     }
   }