Change merge_request_diff_cache_service_spec.rbdz-cache-namespace-methods

Don't stub Rails.cache.write in tests. For example introducing cache for
Project#full_path breaks merge_request_diff_cache_service_spec.rb
because latest one expected that no other code will use Rails.cache.write
during test.

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

2 files changed, 8 insertions, 5 deletions

diff --git a/spec/models/concerns/cache_method_spec.rb b/spec/models/concerns/cache_method_spec.rb
index e44bb146fff..fb72bc9f7e9 100644
--- a/spec/models/concerns/cache_method_spec.rb
+++ b/spec/models/concerns/cache_method_spec.rb
@@ -38,6 +38,7 @@ describe CacheMethod, caching: true do
   describe 'expire_method_caches' do
     it 'expires cache and returns new value' do
       subject.expire_method_caches(%w(time))
+
       expect(subject.time).not_to eq(time)
     end
   end
diff --git a/spec/services/merge_requests/merge_request_diff_cache_service_spec.rb b/spec/services/merge_requests/merge_request_diff_cache_service_spec.rb
index 35804d41b46..1069647a34e 100644
--- a/spec/services/merge_requests/merge_request_diff_cache_service_spec.rb
+++ b/spec/services/merge_requests/merge_request_diff_cache_service_spec.rb
@@ -1,19 +1,21 @@
 require 'spec_helper'
 
-describe MergeRequests::MergeRequestDiffCacheService do
+describe MergeRequests::MergeRequestDiffCacheService, services: true do
   let(:subject) { MergeRequests::MergeRequestDiffCacheService.new }
+  let(:merge_request) { create(:merge_request) }
 
-  describe '#execute' do
+  describe '#execute', caching: true do
     it 'retrieves the diff files to cache the highlighted result' do
-      merge_request = create(:merge_request)
       cache_key = [merge_request.merge_request_diff, 'highlighted-diff-files', Gitlab::Diff::FileCollection::MergeRequestDiff.default_options]
 
-      expect(Rails.cache).to receive(:read).with(cache_key).and_return({})
-      expect(Rails.cache).to receive(:write).with(cache_key, anything)
       allow_any_instance_of(Gitlab::Diff::File).to receive(:blob).and_return(double("text?" => true))
       allow_any_instance_of(Repository).to receive(:diffable?).and_return(true)
 
+      expect(Rails.cache.read(cache_key)).to be_blank
+
       subject.execute(merge_request)
+
+      expect(Rails.cache.read(cache_key)).to be_present
     end
   end
 end