The Ruby Spec Suite
The Ruby Spec Suite, abbreviated
ruby/spec, is a test suite for the behavior of the Ruby programming language.
Description and Motivation
It is not a standardized specification like the ISO one, and does not aim to become one. Instead, it is a practical tool to describe and test the behavior of Ruby with code.
Every example code has a textual description, which presents several advantages:
- It is easier to understand the intent of the author
- It documents how recent versions of Ruby should behave
- It helps Ruby implementations to agree on a common behavior
The specs are written with syntax similar to RSpec 2. They are run with MSpec, the purpose-built framework for running the Ruby Spec Suite. For more information, see the MSpec project.
The specs describe the language syntax, the core library, the standard library, the C API for extensions and the command line flags. The language specs are grouped by keyword while the core and standard library specs are grouped by class and method.
ruby/spec is known to be tested in these implementations for every commit:
ruby/spec describes the behavior of Ruby 2.6 and more recent Ruby versions. More precisely, every latest stable MRI release should pass all specs of ruby/spec (2.6.x, 2.7.x, 3.0.x, etc), and those are tested in CI.
Synchronization with Ruby Implementations
The specs are synchronized both ways around once a month by @eregon between ruby/spec, MRI, JRuby and TruffleRuby,
using this script.
Each of these repositories has a full copy of the specs under
spec/ruby to ease editing specs.
Any of these repositories can be used to add or edit specs, use what is most convenient for you.
For testing the development version of a Ruby implementation, one should always test against that implementation's copy of the specs under
spec/ruby, as that's what the Ruby implementation tests against in their CI.
Also, this repository doesn't always contain the latest spec changes from MRI (it's synchronized monthly), and does not contain tags (specs marked as failing on that Ruby implementation).
Running specs on a Ruby implementation can be done with:
$ cd ruby_implementation/spec/ruby # Add ../ruby_implementation/bin in PATH, or pass -t /path/to/bin/ruby $ ../mspec/bin/mspec
Specs for old Ruby versions
For older specs try these commits:
- Ruby 2.0.0-p647 - Suite using MSpec (may encounter 2 failures)
- Ruby 2.1.9 - Suite using MSpec
- Ruby 2.2.10 - Suite using MSpec
- Ruby 2.3.8 - Suite using MSpec
- Ruby 2.4.10 - Suite using MSpec
- Ruby 2.5.9 - Suite using MSpec
Running the specs
First, clone this repository:
$ git clone https://github.com/ruby/spec.git
Then move to it:
$ cd spec
$ git clone https://github.com/ruby/mspec.git ../mspec
And run the spec suite:
This will execute all the specs using the executable named
ruby on your current PATH.
Running Specs with a Specific Ruby Implementation
-t option to specify the Ruby implementation with which to run the specs.
The argument is either a full path to the Ruby binary, or an executable in
$ ../mspec/bin/mspec -t /path/to/some/bin/ruby
Running Selected Specs
To run a single spec file, pass the filename to
$ ../mspec/bin/mspec core/kernel/kind_of_spec.rb
You can also pass a directory, in which case all specs in that directories will be run:
$ ../mspec/bin/mspec core/kernel
Finally, you can also run them per group as defined in
The following command will run all language specs:
$ ../mspec/bin/mspec :language
In similar fashion, the following commands run the respective specs:
$ ../mspec/bin/mspec :core $ ../mspec/bin/mspec :library $ ../mspec/bin/mspec :capi
Sanity Checks When Running Specs
A number of checks for various kind of "leaks" (file descriptors, temporary files,
ARGV, global encodings, top-level constants) can be
$ CHECK_LEAKS=true ../mspec/bin/mspec
New top-level constants should only be introduced when needed or follow the
<ClassBeingTested>Specs such as
Other constants used for testing should be nested under such a module.
Exceptions to these rules are contained in the file
MSpec can automatically add new top-level constants in this file with:
$ CHECK_LEAKS=save mspec ../mspec/bin/mspec file
Contributing and Writing Specs
See CONTRIBUTING.md for documentation about contributing and writing specs (guards, matchers, etc).
These command-line executables are needed to run the specs.
findutils, not needed on Windows)
/etc/services is required for socket specs (package
netbase on Debian, not needed on Windows).
Socket specs from rubysl-socket
Most specs under
library/socket were imported from the rubysl-socket project.
The 3 copyright holders of rubysl-socket, Yorick Peterse, Chuck Remes and
Brian Shirai, agreed to relicense those specs
under the MIT license in ruby/spec.
History and RubySpec
This project was originally born from Rubinius tests being converted to the spec style. The revision history of these specs is available here. These specs were later extracted to their own project, RubySpec, with a specific vision and principles. At the end of 2014, Brian Shirai, the creator of RubySpec, decided to end RubySpec. A couple months later, the different repositories were merged and the project was revived. On 12 January 2016, the name was changed to "The Ruby Spec Suite" for clarity and to let the RubySpec ideology rest in peace.