Speed up running unit tests with Zeus

This is an effort to vastly decrease the time it takes to run a single
unit test file and therefore increase productivity and happiness for
people working on this project.

If you want to run a unit test file, now you can use `zeus rspec`
instead of `rspec` -- assuming you run `zeus start` first -- and it will
run a LOT faster.

Because test files tend to have long file paths, you can even use a
shorter version of those paths. So instead of saying:

    zeus rspec spec/unit/shoulda/matchers/active_record/validate_uniqueness_of_matcher_spec.rb

you can say:

    zeus rspec active_record/validate_uniqueness_of_matcher_spec.rb

CONTRIBUTING.md

@@ -37,6 +37,13 @@ request.
    appraisal 4.2 rspec <path of test file to run>
    ```
 
+   You can also run unit tests by running `zeus start` in one shell, and then
+   running the following in another:
+
+   ```
+   zeus rspec <path of test file to run>
+   ```
+
    And to run the entire test suite again:
 
    ```

Gemfile

@@ -6,6 +6,7 @@ gem 'pry', github: 'pry/pry'
 gem 'pry-byebug'
 gem 'rake', '~> 10.0'
 gem 'rspec', '~> 3.2'
+gem 'zeus'
 
 # YARD
 gem 'yard'

Gemfile.lock

@@ -47,6 +47,8 @@ GEM
     thor (0.19.1)
     yajl-ruby (1.1.0)
     yard (0.8.7.3)
+    zeus (0.15.4)
+      method_source (>= 0.6.7)
 
 PLATFORMS
   ruby
@@ -62,6 +64,4 @@ DEPENDENCIES
   redcarpet
   rspec (~> 3.2)
   yard
-
-BUNDLED WITH
-   1.10.6
+  zeus

README.md

@@ -221,6 +221,52 @@ Shoulda::Matchers.configure do |config|
 end
 ```
 
+## Running tests
+
+### Unit tests
+
+Unit tests are the most common kind of tests in this gem, and the best way to
+run them is by using [Zeus].
+
+You'll want to run `zeus start` in one shell, then in another shell, instead of
+using `rspec` to run tests, you can use `zeus rspec`. So for instance, you might
+say:
+
+```
+zeus rspec spec/unit/shoulda/matchers/active_model/validate_inclusion_of_matcher_spec.rb
+```
+
+As a shortcut, you can also drop the initial part of the path and say this
+instead:
+
+```
+zeus rspec active_model/validate_inclusion_of_matcher_spec.rb
+```
+
+### Acceptance tests
+
+The gem uses [Appraisal] to test against multiple versions of Rails and Ruby.
+This means that if you're trying to run a single test file, you'll need to
+specify which appraisal to use. For instance, you can't simply say:
+
+```
+rspec spec/acceptance/active_model_integration_spec.rb
+```
+
+Instead, you need to say
+
+```
+bundle exec appraisal 4.2 rspec spec/acceptance/active_model_integration_spec.rb
+```
+
+### All tests
+
+You can run all tests by saying:
+
+```
+bundle exec rake
+```
+
 ## Generating documentation
 
 YARD is used to generate documentation, which can be viewed [online][rubydocs].
@@ -284,3 +330,5 @@ We are [available for hire][hire].
 [contributors]: https://github.com/thoughtbot/shoulda-matchers/contributors
 [shoulda]: http://github.com/thoughtbot/shoulda
 [shoulda-context]: http://github.com/thoughtbot/shoulda-context
+[Zeus]: https://github.com/burke/zeus
+[Appraisal]: https://github.com/thoughtbot/appraisal

custom_plan.rb

@@ -0,0 +1,88 @@
+require 'zeus/rails'
+require_relative 'spec/support/tests/current_bundle'
+
+class CustomPlan < Zeus::Plan
+  def initialize
+    super
+    @rails_plan = Zeus::Rails.new
+  end
+
+  def boot
+    ENV['BUNDLE_GEMFILE'] = File.expand_path(
+      "../gemfiles/#{latest_appraisal}.gemfile",
+      __FILE__
+    )
+
+    require 'bundler/setup'
+
+    $LOAD_PATH << File.expand_path('../lib', __FILE__)
+    $LOAD_PATH << File.expand_path('../spec', __FILE__)
+
+    require_relative 'spec/support/unit/load_environment'
+  end
+
+  def after_fork
+    # @rails_plan.reconnect_activerecord
+  end
+
+  def test_environment
+    require_relative 'spec/unit_spec_helper'
+  end
+
+  def rspec
+    ARGV.replace(file_paths_to_run)
+    RSpec::Core::Runner.invoke
+  end
+
+  private
+
+  def latest_appraisal
+    current_bundle.latest_appraisal
+  end
+
+  def current_bundle
+    Tests::CurrentBundle.instance
+  end
+
+  def file_paths_to_run
+    if given_file_paths.empty?
+      ['spec/unit']
+    else
+      given_file_paths.map do |given_path|
+        determine_file_path_to_run(given_path)
+      end
+    end
+  end
+
+  def determine_file_path_to_run(given_rspec_argument)
+    expanded_file_path, location =
+      expand_rspec_argument(given_rspec_argument)
+
+    if File.exist?(expanded_file_path)
+      if location
+        expanded_file_path + location
+      else
+        expanded_file_path
+      end
+    else
+      given_rspec_argument
+    end
+  end
+
+  def expand_rspec_argument(rspec_argument)
+    match = rspec_argument.match(/\A(.+?)(:\d+|\[[\d:]+\])?\Z/)
+    file_path, location = match.captures
+    expanded_file_path = File.expand_path(
+      "../spec/unit/shoulda/matchers/#{file_path}",
+      __FILE__
+    )
+
+    [expanded_file_path, location]
+  end
+
+  def given_file_paths
+    ARGV
+  end
+end
+
+Zeus.plan = CustomPlan.new

gemfiles/4.0.0.gemfile

@@ -8,6 +8,7 @@ gem "pry", :github => "pry/pry"
 gem "pry-byebug"
 gem "rake", "~> 10.0"
 gem "rspec", "~> 3.2"
+gem "zeus"
 gem "yard"
 gem "redcarpet"
 gem "pygments.rb"

gemfiles/4.0.0.gemfile.lock

@@ -177,6 +177,8 @@ GEM
       json (>= 1.8.0)
     yajl-ruby (1.2.1)
     yard (0.8.7.6)
+    zeus (0.15.4)
+      method_source (>= 0.6.7)
 
 PLATFORMS
   ruby
@@ -215,6 +217,4 @@ DEPENDENCIES
   turbolinks
   uglifier (>= 1.3.0)
   yard
-
-BUNDLED WITH
-   1.10.6
+  zeus

gemfiles/4.0.1.gemfile

@@ -8,6 +8,7 @@ gem "pry", :github => "pry/pry"
 gem "pry-byebug"
 gem "rake", "~> 10.0"
 gem "rspec", "~> 3.2"
+gem "zeus"
 gem "yard"
 gem "redcarpet"
 gem "pygments.rb"

gemfiles/4.0.1.gemfile.lock

@@ -179,6 +179,8 @@ GEM
       json (>= 1.8.0)
     yajl-ruby (1.2.1)
     yard (0.8.7.6)
+    zeus (0.15.4)
+      method_source (>= 0.6.7)
 
 PLATFORMS
   ruby
@@ -217,6 +219,4 @@ DEPENDENCIES
   turbolinks
   uglifier (>= 1.3.0)
   yard
-
-BUNDLED WITH
-   1.10.6
+  zeus

gemfiles/4.1.gemfile

@@ -8,6 +8,7 @@ gem "pry", :github => "pry/pry"
 gem "pry-byebug"
 gem "rake", "~> 10.0"
 gem "rspec", "~> 3.2"
+gem "zeus"
 gem "yard"
 gem "redcarpet"
 gem "pygments.rb"

gemfiles/4.1.gemfile.lock

@@ -174,6 +174,8 @@ GEM
       json (>= 1.8.0)
     yajl-ruby (1.2.1)
     yard (0.8.7.6)
+    zeus (0.15.4)
+      method_source (>= 0.6.7)
 
 PLATFORMS
   ruby
@@ -212,6 +214,4 @@ DEPENDENCIES
   turbolinks
   uglifier (>= 1.3.0)
   yard
-
-BUNDLED WITH
-   1.10.6
+  zeus

gemfiles/4.2.gemfile

@@ -8,6 +8,7 @@ gem "pry", :github => "pry/pry"
 gem "pry-byebug"
 gem "rake", "~> 10.0"
 gem "rspec", "~> 3.2"
+gem "zeus"
 gem "yard"
 gem "redcarpet"
 gem "pygments.rb"

gemfiles/4.2.gemfile.lock

@@ -197,6 +197,8 @@ GEM
       json (>= 1.8.0)
     yajl-ruby (1.2.1)
     yard (0.8.7.6)
+    zeus (0.15.4)
+      method_source (>= 0.6.7)
 
 PLATFORMS
   ruby
@@ -235,6 +237,4 @@ DEPENDENCIES
   turbolinks
   uglifier (>= 1.3.0)
   yard
-
-BUNDLED WITH
-   1.10.6
+  zeus

spec/support/tests/current_bundle.rb

@@ -24,6 +24,10 @@ def appraisal_in_use?
       path.dirname == root.join('gemfiles')
     end
 
+    def current_or_latest_appraisal
+      current_appraisal || latest_appraisal
+    end
+
     def latest_appraisal
       available_appraisals.sort.last
     end

spec/support/unit/load_environment.rb

@@ -0,0 +1,12 @@
+require_relative '../tests/current_bundle'
+require_relative 'rails_application'
+
+Tests::CurrentBundle.instance.assert_appraisal!
+
+$test_app = UnitTests::RailsApplication.new
+$test_app.create
+$test_app.load
+
+require 'active_record/base'
+
+ENV['RAILS_ENV'] = 'test'

spec/unit_spec_helper.rb

@@ -1,19 +1,4 @@
-require_relative 'support/tests/current_bundle'
-
-Tests::CurrentBundle.instance.assert_appraisal!
-
-#---
-
-require File.expand_path('../support/unit/rails_application', __FILE__)
-
-$test_app = UnitTests::RailsApplication.new
-$test_app.create
-$test_app.load
-
-require 'active_record/base'
-
-ENV['BUNDLE_GEMFILE'] ||= app.gemfile_path
-ENV['RAILS_ENV'] = 'test'
+require_relative 'support/unit/load_environment'
 
 require 'rspec/rails'
 require 'shoulda-matchers'

zeus.json

@@ -0,0 +1,11 @@
+{
+  "command": "ruby -rubygems -r./custom_plan -eZeus.go",
+
+  "plan": {
+    "boot": {
+      "test_environment": {
+        "rspec": []
+      }
+    }
+  }
+}