RSpecDissect

Do you know how much time you spend in before hooks? Or in memoization helpers such as let? Usually, the most of the whole test suite time.

RSpecDissect provides this kind of information and also shows you the worst example groups. The main purpose of RSpecDissect is to identify these slow groups and refactor them using before_all or let_it_be recipes.

Example output:

[TEST PROF INFO] RSpecDissect enabled

Total time: 25:14.870
Total `before(:each)` time: 14:36.482
Total `let` time: 19:20.259

Top 5 slowest suites (by `before(:each)` time):

Webhooks::DispatchTransition (./spec/services/webhooks/dispatch_transition_spec.rb:3) – 00:29.895 of 00:33.706 (327)
FunnelsController (./spec/controllers/funnels_controller_spec.rb:3) – 00:22.117 of 00:43.649 (133)
ApplicantsController (./spec/controllers/applicants_controller_spec.rb:3) – 00:21.220 of 00:41.407 (222)
BookedSlotsController (./spec/controllers/booked_slots_controller_spec.rb:3) – 00:15.729 of 00:27.893 (50)
Analytics::Wor...rsion::Summary (./spec/services/analytics/workflow_conversion/summary_spec.rb:3) – 00:15.383 of 00:15.914 (12)


Top 5 slowest suites (by `let` time):

FunnelsController (./spec/controllers/funnels_controller_spec.rb:3) – 00:38.532 of 00:43.649 (133)
 ↳ user – 3
 ↳ funnel – 2
ApplicantsController (./spec/controllers/applicants_controller_spec.rb:3) – 00:33.252 of 00:41.407 (222)
 ↳ user – 10
 ↳ funnel – 5
 ↳ applicant – 2
Webhooks::DispatchTransition (./spec/services/webhooks/dispatch_transition_spec.rb:3) – 00:30.320 of 00:33.706 (327)
 ↳ user – 30
BookedSlotsController (./spec/controllers/booked_slots_controller_spec.rb:3) – 00:25.710 of 00:27.893 e(50)
 ↳ user – 21
 ↳ stage – 14
AvailableSlotsController (./spec/controllers/available_slots_controller_spec.rb:3) – 00:18.481 of 00:23.366 (85)
 ↳ user – 15
 ↳ stage – 10

As you can see, the let profiler also tracks the provides the information on how many times each let declarations has been used within a group (shows top-3 by default).

Instructions

RSpecDissect can only be used with RSpec (which is clear from the name).

To activate RSpecDissect use RD_PROF environment variable:

RD_PROF=1 rspec ...

You can also specify the number of top slow groups through RD_PROF_TOP variable:

RD_PROF=1 RD_PROF_TOP=10 rspec ...

You can also track only let or before usage by specifying RD_PROF=let and RD_PROF=before respectively.

For let profiler you can also specify the number of top let declarations to print through RD_PROF_LET_TOP=10 env var.

To disable let stats add:

TestProf::RSpecDissect.configure do |config|
  config.let_stats_enabled = false
end

Using with RSpecStamp

RSpecDissect can be used with RSpec Stamp to automatically mark slow examples with custom tags. For example:

RD_PROF=1 RD_PROF_STAMP="slow" rspec ...

After running the command above the slowest example groups would be marked with the :slow tag.