Recover usage of Todos counter cache

We’re being kept up to date the counter data but we’re not using it.
The only thing which is not real if is the number of projects that the 
user read changes the number of todos can be stale for some time.

The counters will be sync just after the user receives a new todo or mark any as done

1 files changed, 36 insertions, 0 deletions

diff --git a/spec/services/todo_service_spec.rb b/spec/services/todo_service_spec.rb
index 34d8ea9090e..6c3cbeae13c 100644
--- a/spec/services/todo_service_spec.rb
+++ b/spec/services/todo_service_spec.rb
@@ -472,6 +472,42 @@ describe TodoService, services: true do
     expect(john_doe.todos_pending_count).to eq(1)
   end
 
+  describe '#mark_todos_as_done' do
+    let(:issue) { create(:issue, project: project, author: author, assignee: john_doe) }
+
+    it 'marks a relation of todos as done' do
+      create(:todo, :mentioned, user: john_doe, target: issue, project: project)
+
+      todos = TodosFinder.new(john_doe, {}).execute
+      expect { TodoService.new.mark_todos_as_done(todos, john_doe) }
+       .to change { john_doe.todos.done.count }.from(0).to(1)
+    end
+
+    it 'marks an array of todos as done' do
+      todo = create(:todo, :mentioned, user: john_doe, target: issue, project: project)
+
+      expect { TodoService.new.mark_todos_as_done([todo], john_doe) }
+        .to change { todo.reload.state }.from('pending').to('done')
+    end
+
+    it 'returns the number of updated todos' do # Needed on API
+      todo = create(:todo, :mentioned, user: john_doe, target: issue, project: project)
+
+      expect(TodoService.new.mark_todos_as_done([todo], john_doe)).to eq(1)
+    end
+
+    it 'caches the number of todos of a user', :caching do
+      create(:todo, :mentioned, user: john_doe, target: issue, project: project)
+      todo = create(:todo, :mentioned, user: john_doe, target: issue, project: project)
+      TodoService.new.mark_todos_as_done([todo], john_doe)
+
+      expect_any_instance_of(TodosFinder).not_to receive(:execute)
+
+      expect(john_doe.todos_done_count).to eq(1)
+      expect(john_doe.todos_pending_count).to eq(1)
+    end
+  end
+
   def should_create_todo(attributes = {})
     attributes.reverse_merge!(
       project: project,