CE backport for changes in EE MR 13389

This backports to ce a refactor of the shared example 'a controller that
can serve LFS files'.

The ee MR that contains the original refactor is
https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/13389

The reason for the refactor was mostly the removal of the outer context
as it didn't need to be there, and prevented let(:lfs_oid) from being
overwritten.

The shared example was also renamed to be more descriptive.

spec/controllers/projects/avatars_controller_spec.rb

@@ -39,7 +39,7 @@ describe Projects::AvatarsController do
       end
 
       context 'when the avatar is stored in lfs' do
-        it_behaves_like 'repository lfs file load' do
+        it_behaves_like 'a controller that can serve LFS files' do
           let(:filename) { 'lfs_object.iso' }
           let(:filepath) { "files/lfs/#{filename}" }
         end

spec/controllers/projects/raw_controller_spec.rb

@@ -42,7 +42,7 @@ describe Projects::RawController do
       end
     end
 
-    it_behaves_like 'repository lfs file load' do
+    it_behaves_like 'a controller that can serve LFS files' do
       let(:filename) { 'lfs_object.iso' }
       let(:filepath) { "be93687/files/lfs/#{filename}" }
     end

spec/support/shared_examples/controllers/repository_lfs_file_load_examples.rb

@@ -9,8 +9,7 @@
 # - `filepath`: path of the file (contains filename)
 # - `subject`: the request to be made to the controller. Example:
 # subject { get :show, namespace_id: project.namespace, project_id: project }
-shared_examples 'repository lfs file load' do
-  context 'when file is stored in lfs' do
+shared_examples 'a controller that can serve LFS files' do
   let(:lfs_oid) { '91eff75a492a3ed0dfcb544d7f31326bc4014c8551849c192fd1e48d4dd2c897' }
   let(:lfs_size) { '1575078' }
   let!(:lfs_object) { create(:lfs_object, oid: lfs_oid, size: lfs_size) }
@@ -28,11 +27,13 @@ shared_examples 'repository lfs file load' do
       end
 
       it 'serves the file' do
+        lfs_uploader = LfsObjectUploader.new(lfs_object)
+
         # Notice the filename= is omitted from the disposition; this is because
         # Rails 5 will append this header in send_file
         expect(controller).to receive(:send_file)
                           .with(
-                              "#{LfsObjectUploader.root}/91/ef/f75a492a3ed0dfcb544d7f31326bc4014c8551849c192fd1e48d4dd2c897",
+                            File.join(lfs_uploader.root, lfs_uploader.store_dir, lfs_uploader.filename),
                             filename: filename,
                             disposition: %Q(attachment; filename*=UTF-8''#{filename}))
 
@@ -62,7 +63,7 @@ shared_examples 'repository lfs file load' do
           file_uri = URI.parse(response.location)
           params = CGI.parse(file_uri.query)
 
-            expect(params["response-content-disposition"].first).to eq(%q(attachment; filename="lfs_object.iso"; filename*=UTF-8''lfs_object.iso))
+          expect(params["response-content-disposition"].first).to eq(%Q(attachment; filename="#{filename}"; filename*=UTF-8''#{filename}))
         end
       end
     end
@@ -91,5 +92,4 @@ shared_examples 'repository lfs file load' do
       expect(response.header[Gitlab::Workhorse::SEND_DATA_HEADER]).to start_with('git-blob:')
     end
   end
-  end
 end