add controller tests

test/models/supported_language_test.rb

@@ -2,13 +2,12 @@ require "test_helper"
 
 class SupportedLanguageTest < ActiveSupport::TestCase
   test "should be valid with all attributes" do
-    language = SupportedLanguage.new(code: "es", name: "Spanish", native_name: "Español")
+    language = SupportedLanguage.new(code: "sv", name: "Swedish", native_name: "Svenska")
     assert language.valid?
   end
 
   test "should be invalid with a duplicate code" do
-    SupportedLanguage.create(code: "de", name: "German", native_name: "Deutsch")
-    language = SupportedLanguage.new(code: "de", name: "German", native_name: "Deutsch")
+    language = SupportedLanguage.new(code: supported_languages(:one).code, name: "English", native_name: "English")
     assert_not language.valid?
   end
 end