The RSpec Toolbox

From WindyCityRails 2012

Presenter: David Chelimsky

Summary

Lots of tips and tricks for using RSpec, including some lesser known ones (like tags/filters) and easier command line usage.

Notes

From @benjaminoakes:

• DRW Trading Group (hiring)
• Rspec2
  • Micronaut: Each example has its own metadata
  • New basis for Rspec

Basically the Command pattern:

example_group = describe Something { }

example = it 'does something' { }

• Used in output at command line, etc.
• rspec has formatter methods (there's an protocol with an interface)
  • Example formatters:
    • Documentation
    • HTML
    • 3rd party
      • Instafail: shows you error messages early
      • Fuubar
      • NyanCat
• Focusing tools
  • autotest, guard -- monitor changes to files and re-run specs
  • Sometimes you don't want it to rerun everything again (e.g., if you TDD)... so, focus!

config.filter_run_including :focus => true

it 'something', :focus => true do
end

Or exclude stuff:

config.filter_run_excluding :slow => true

it 'something', :slow => true do
end

Shorthand:

# Will be default in the future...
config.treat_symbols_as_metadata_keys_with_true_values = true

it 'something', :slow do
end

it 'something', :focus do
end

conditional filters

describe Thing, :if => RUBY_VERSON >= "1.9" do
end

describe Thing, :if => ENV['GENERATE'] do
end

Can have specialized groups (what they do in rspec-rails -- look at it for examples):

RSpec::configure do |c|
  # Gist: if in this path, include this behavior
end

Or just always use, say, FakeFS:

RSpec.configure do |config|
  config.include FakeFS::SpecHelpers, :fakefs
end

describe 'something that writes files', :fakefs => true edo
  # ...
  # Or:  `include FakeFS::SpecHelpers`
  # TODO: can you have it output something too?  Like in the `documentation` formatter?
end

Can also alias example (as it, xit, pending, etc.)

Config stuff

c.default_path = "./behavior" # normally "./spec"
c.fail_fast = true

Command Line

rspec can be much faster than rake because of how rake loads (with a sub shell)

Options

--tag is for filters

rspec --tag focus:true
rspec --tag ~slow:true
rspec --tag ~slow:true --tag issue:123 # Might have been written down incorrectly

Local options: ./.rspec

--color
--order random
--format progress
--profile

Global options: ~/.rspec

Works the same way

Single run options

With --options at the command line, you can point to a file that has:

--tag issue:123

(pro tip about how to organize; see slides)

Expectations