Add some api integration tests (go-gitea#18872)

depends on go-gitea#18871

Added some api integration tests to help testing of go-gitea#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/attachment.yml

@@ -3,104 +3,140 @@
   uuid: a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11
   repo_id: 1
   issue_id: 1
+  release_id: 0
+  uploader_id: 0
   comment_id: 0
   name: attach1
   download_count: 0
+  size: 0
   created_unix: 946684800
 
 -
   id: 2
   uuid: a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a12
   repo_id: 2
   issue_id: 4
+  release_id: 0
+  uploader_id: 0
   comment_id: 0
   name: attach2
   download_count: 1
+  size: 0
   created_unix: 946684800
 
 -
   id: 3
   uuid: a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a13
   repo_id: 1
   issue_id: 2
+  release_id: 0
+  uploader_id: 0
   comment_id: 1
   name: attach1
   download_count: 0
+  size: 0
   created_unix: 946684800
 
 -
   id: 4
   uuid: a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a14
   repo_id: 1
   issue_id: 3
+  release_id: 0
+  uploader_id: 0
   comment_id: 1
   name: attach2
   download_count: 1
+  size: 0
   created_unix: 946684800
 
 -
   id: 5
   uuid: a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a15
   repo_id: 2
   issue_id: 4
+  release_id: 0
+  uploader_id: 0
   comment_id: 0
   name: attach1
   download_count: 0
+  size: 0
   created_unix: 946684800
 
 -
   id: 6
   uuid: a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a16
   repo_id: 1
   issue_id: 5
+  release_id: 0
+  uploader_id: 0
   comment_id: 2
   name: attach1
   download_count: 0
+  size: 0
   created_unix: 946684800
 
 -
   id: 7
   uuid: a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a17
   repo_id: 1
   issue_id: 5
+  release_id: 0
+  uploader_id: 0
   comment_id: 2
   name: attach1
   download_count: 0
+  size: 0
   created_unix: 946684800
 
 -
   id: 8
   uuid: a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a18
   repo_id: 3
   issue_id: 6
+  release_id: 0
+  uploader_id: 0
   comment_id: 0
   name: attach1
   download_count: 0
+  size: 0
   created_unix: 946684800
 
 -
   id: 9
   uuid: a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a19
   repo_id: 1
+  issue_id: 0
   release_id: 1
+  uploader_id: 0
+  comment_id: 0
   name: attach1
   download_count: 0
+  size: 0
   created_unix: 946684800
 
 -
   id: 10
   uuid: a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a20
   repo_id: 0 # TestGetAttachment/NotLinked
+  issue_id: 0
+  release_id: 0
   uploader_id: 8
+  comment_id: 0
   name: attach1
   download_count: 0
+  size: 0
   created_unix: 946684800
 
 -
   id: 11
   uuid: a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a21
   repo_id: 40
+  issue_id: 0
   release_id: 2
+  uploader_id: 0
+  comment_id: 0
   name: attach1
   download_count: 0
+  size: 0
   created_unix: 946684800