Fix failing tests relating to backporting ee!581.

1. `GitPushService` was still using `{merge,push}_access_level_attributes` instead
   of `{merge,push}_access_levels_attributes`.

2. The branches API creates access levels regardless of the state of the
   `developers_can_{push,merge}` parameters. This is in line with the UI,
   where Master access is the default for a new protected branch.

3. Use `after(:build)` to create access levels in the
   `protected_branches` factory, so that `factories_spec` passes. It
   only builds records, so we need to create access levels on `build` as
   well.

1 files changed, 17 insertions, 12 deletions

diff --git a/lib/api/branches.rb b/lib/api/branches.rb
index a77afe634f6..b615703df93 100644
--- a/lib/api/branches.rb
+++ b/lib/api/branches.rb
@@ -61,22 +61,27 @@ module API
           name: @branch.name
         }
 
-        unless developers_can_merge.nil?
-          protected_branch_params.merge!({
-            merge_access_level_attributes: {
-              access_level: developers_can_merge ? Gitlab::Access::DEVELOPER : Gitlab::Access::MASTER
-            }
-          })
+        # If `developers_can_merge` is switched off, _all_ `DEVELOPER`
+        # merge_access_levels need to be deleted.
+        if developers_can_merge == false
+          protected_branch.merge_access_levels.where(access_level: Gitlab::Access::DEVELOPER).destroy_all
         end
 
-        unless developers_can_push.nil?
-          protected_branch_params.merge!({
-            push_access_level_attributes: {
-              access_level: developers_can_push ? Gitlab::Access::DEVELOPER : Gitlab::Access::MASTER
-            }
-          })
+        # If `developers_can_push` is switched off, _all_ `DEVELOPER`
+        # push_access_levels need to be deleted.
+        if developers_can_push == false
+          protected_branch.push_access_levels.where(access_level: Gitlab::Access::DEVELOPER).destroy_all
         end
 
+        protected_branch_params.merge!(
+          merge_access_levels_attributes: [{
+            access_level: developers_can_merge ? Gitlab::Access::DEVELOPER : Gitlab::Access::MASTER
+          }],
+          push_access_levels_attributes: [{
+            access_level: developers_can_push ? Gitlab::Access::DEVELOPER : Gitlab::Access::MASTER
+          }]
+        )
+
         if protected_branch
           service = ProtectedBranches::UpdateService.new(user_project, current_user, protected_branch_params)
           service.execute(protected_branch)