Add some api integration tests (#18872)

depends on #18871

Added some api integration tests to help testing of #18798.

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

models/fixtures/topic.yml

@@ -8,18 +8,22 @@
   name: database
   repo_count: 1
 
-- id: 3
+-
+  id: 3
   name: SQL
   repo_count: 1
 
-- id: 4
+-
+  id: 4
   name: graphql
   repo_count: 1
 
-- id: 5
+-
+  id: 5
   name: topicname1
   repo_count: 1
 
-- id: 6
+-
+  id: 6
   name: topicname2
   repo_count: 2