Document published controller integration tests

Explain what is being tested and if it is a FRONTEND, BACKEND or
INTEGRATION test.

Co-authored-by: Moisés Déniz Alemán <mdeniz@suse.com>
Co-authored-by: Adrian Schröter <adrian@suse.de>

src/api/test/functional/published_controller_test.rb

@@ -9,6 +9,7 @@ def setup
     reset_auth
   end
 
+  # FRONTEND: Test published api
   def test_index
     get '/published'
     assert_response 401
@@ -156,8 +157,11 @@ def test_rpm_md_formats
   end
 
   def test_suse_format
+    # Ensure that it doesn't fail in non SUSE platforms TODO: Move this to a method
     return unless File.exist?('/var/adm/fillup-templates') || File.exist?('/usr/share/fillup-templates/')
     login_adrian
+
+    # BACKEND: Test that tooling used in the backend produce correct content via the api in the frontend
     get '/published/BaseDistro3/BaseDistro3_repo/content'
     assert_response :success
     assert_match(/PRODUCT Open Build Service BaseDistro3 BaseDistro3_repo\n/, @response.body)
@@ -170,6 +174,9 @@ def test_suse_format
     assert_match(/\nDEFAULTBASE i586\n/, @response.body)
     assert_match(/\nDESCRDIR descr\n/, @response.body)
     assert_match(/\nDATADIR .\n/, @response.body)
+
+    # BACKEND: Test that the content generated by the backend tooling is creating some subdirectory in a concrete way
+    # FRONTEND: Test that the subdirectories created by the backend can be accessed thought the API in the frontend
     get '/published/BaseDistro3/BaseDistro3_repo/media.1/directory.yast'
     assert_response :success
     get '/published/BaseDistro3/BaseDistro3_repo/media.1/media'