Parallel tests
in comparable time
Artur Trzop
X 2014
A long time ago
many, many commits ago
Build was green
and fast
Tests were even faster
But winter finally came
Actually it was summer
and build was sl w
Save time
&
get faster feedback
Parallel specs
splitting your test suite
Test suite example
1_fast_spec.rb
2_fast_spec.rb
3_fast_spec.rb
4_fast_spec.rb
5_slow_spec.rb
6_slow_spec.rb
7_slow_spec.rb
8_super_slow_spec.rb
Balancing
split all test files across N nodes:
Node 1
1_fast_spec.rb
2_fast_spec.rb
Node 2
3_fast_spec.rb
4_fast_spec.rb
Node 3
5_slow_spec.rb
6_slow_spec.rb
Node 4
7_slow_spec.rb
8_super_slow_spec.rb
It ends up like this...
Time for the rescue
let's split tests based on the time execution
with
Knapsack
gem
Node 1
8_super_slow_spec.rb
Node 2
7_slow_spec.rb
4_fast_spec.rb
1_fast_spec.rb
Node 3
6_slow_spec.rb
3_fast_spec.rb
Node 4
5_slow_spec.rb
2_fast_spec.rb
How ab ut time
How to set up Knapsack?
# Gemfile
gem 'knapsack'spec_helper.rb
require 'knapsack'
Knapsack::Adapters::RspecAdapter.bindRakefile
require 'knapsack'
Knapsack.load_tasks Generate time execution report for you spec files
run it on CI machine
$ KNAPSACK_GENERATE_REPORT=true \
bundle exec rspec specCommit generated report
into your repository
knapsack_report.json
Setup your CI server
$ CI_NODE_TOTAL=2 CI_NODE_INDEX=0 \
bundle exec rake knapsack:rspecThat's it.
What else?
Upcoming features
Cucumber support
shippable.com CI support
