Use travel_to instead of dependency injection, feedback:

app/models/ci/pipeline.rb

@@ -48,11 +48,11 @@ module Ci
       end
 
       before_transition [:created, :pending] => :running do |pipeline|
-        pipeline.started_at = Gitlab::Utils.now
+        pipeline.started_at = Time.now
       end
 
       before_transition any => [:success, :failed, :canceled] do |pipeline|
-        pipeline.finished_at = Gitlab::Utils.now
+        pipeline.finished_at = Time.now
       end
 
       before_transition do |pipeline|

app/models/concerns/statuseable.rb

@@ -87,7 +87,7 @@ module Statuseable
     if started_at && finished_at
       finished_at - started_at
     elsif started_at
-      Gitlab::Utils.now - started_at
+      Time.now - started_at
     end
   end
 end

lib/gitlab/utils.rb

@@ -13,10 +13,5 @@ module Gitlab
     def force_utf8(str)
       str.force_encoding(Encoding::UTF_8)
     end
-
-    # The same as Time.now but using this would make it easier to test
-    def now
-      Time.now
-    end
   end
 end

spec/models/ci/pipeline_spec.rb

@@ -128,11 +128,13 @@ describe Ci::Pipeline, models: true do
 
     describe '#duration' do
       before do
-        allow(Gitlab::Utils).to receive(:now).
-          and_return(current - 120, current)
+        travel_to(current - 120) do
+          pipeline.run
+        end
 
-        pipeline.run
-        pipeline.succeed
+        travel_to(current) do
+          pipeline.succeed
+        end
       end
 
       it 'matches sum of builds duration' do

spec/spec_helper.rb

@@ -33,6 +33,7 @@ RSpec.configure do |config|
   config.include EmailHelpers
   config.include TestEnv
   config.include ActiveJob::TestHelper
+  config.include ActiveSupport::Testing::TimeHelpers
   config.include StubGitlabCalls
   config.include StubGitlabData