Clean up after test

Test suite runs fine without this locally (ruby 2.6.3, Rails 5.2.3), but Travis CI builds all fail because subsequent tests expect a clean base URL.

Signed-off-by: Tobias Grasse <tg@glancr.de>

Author: tobias-grasse

test/controllers/controller_test.rb

@@ -14,6 +14,7 @@ def test_links_include_relative_root
     Rails.application.config.relative_url_root = '/subdir'
     assert_cacheable_get :index
     assert json_response['data'][0]['links']['self'].include?('/subdir')
+    Rails.application.config.relative_url_root = nil
   end
 
   def test_index