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
Parallel tests in comparable time
By ArturT
Parallel tests in comparable time
Knapsack splits tests across CI nodes and makes sure that tests will run comparable time on each node.
