Test/spec 0.9, a BDD interface for Test::Unit


today I’m releasing test/spec 0.9, a library to do BDD with Test::Unit.

== News in 0.9:

  • July 2nd, 2008: Fifth public release 0.9.
    • Allow should.? as well as should..
    • Add shared contexts.
    • Nested contexts now run the
      setups/teardowns/before(:all)/after(:all) of their parents.

== What is test/spec?

test/spec layers an RSpec-inspired interface on top of Test::Unit, so
you can mix TDD and BDD (Behavior-Driven Development).

test/spec is a clean-room implementation that maps most kinds of
Test::Unit assertions to a `should’-like syntax.

Consider this Test::Unit test case:

class TestFoo < Test::Unit::TestCase
  def test_should_bar
    assert_equal 5, 2 + 3

In test/spec, it looks like this:

require 'test/spec'

context "Foo" do
  specify "should bar" do
    (2 + 3).should.equal 5

Since test/spec 0.4, you can also use the new RSpec 1.0 style:

require 'test/spec'

describe "Foo" do
  it "should bar" do
    (2 + 3).should.equal 5

test/spec does not include a mocking/stubbing-framework; use whichever
you like to. test/spec has been tested successfully with FlexMock and

test/spec has no dependencies outside Ruby 1.8.

== Mixing test/spec and test/unit

test/spec and Test::Unit contexts/test cases can be intermixed freely,
run in the same test and live in the same files. You can just add them
to your Rake::TestTask, too. test/spec allows you to leverage your
full existing Test::Unit infrastructure.

test/spec does not change Test::Unit with the exception of
monkey-patching Test::Unit::TestSuite to order the test cases before
running them. (This should not do any harm, but if you know a way
around it, please tell me.)

== Wrapped assertions

assert_equal: should.equal, should ==
assert_not_equal: should.not.equal, should.not ==
assert_same: should.be
assert_not_same: should.not.be
assert_nil: should.be.nil
assert_not_nil: should.not.be.nil

assert_in_delta: should.be.close
assert_match: should.match, should =~
assert_no_match: should.not.match, should.not =~

assert_instance_of: should.be.an.instance_of
assert_kind_of: should.be.a.kind_of
assert_respond_to: should.respond_to

assert_raise: should.raise
assert_nothing_raised: should.not.raise
assert_throws: should.throw
assert_nothing_thrown: should.not.throw
assert_block: should.satisfy

== Additional assertions

These assertions are not included in Test::Unit, but have been added
to test/spec for convenience:

  • should.not.satisfy
  • a.should. (works like assert a.?)
  • a.should.be (where is <, <=, >, >=, or ===)
  • should.output, to check what is printed

== Messaging/Blaming

With more complex assertions, it may be helpful to provide a message
to show if the assertion has failed. This can be done with the
Should#blaming or Should#messaging methods:

RUBY_VERSION.should.messaging("Ruby too old.").be > "1.8.4"

(1 + 1).should.blaming("weird math").not.equal 11

== Custom shoulds (“Matchers”)

To capture recurring patterns in parts of your specifications, you can
define custom “shoulds” (RSpec calls them “matchers”) in your
contexts, or include modules of them:

context "Numbers"
  class EqualString < Test::Spec::CustomShould
    def matches?(other)
      object == other.to_s

  def equal_string(str)

  specify "should have to_s"
    42.should equal_string("42")

Alternatively, your implementation can define
CustomShould#assumptions, where you can use test/spec assertions
instead of Boolean predicates:

class EqualString < Test::Spec::CustomShould
  def assumptions(other)
    object.should.equal other.to_s

A CustomShould by default takes one argument, which is placed in
self.object for your convenience.

You can CustomShould#failure_message to provide a better error

== SpecDox and RDox

test/spec adds two additional test runners to Test::Unit, based on the
console runner but with a different output format.

SpecDox, run with --runner=specdox (or -rs) looks like RSpec’s output:

- works for print
- works for puts
- works with readline

RDox, run with --runner=rdox (or -rr) can be included for RDoc

== should.output
* works for print
* works for puts
* works with readline

SpecDox and RDox work for Test::Unit too:

$ ruby -r test/spec test/testunit/test_testresult.rb -rs

- fault notification
- passed?
- result changed notification

Finished in 0.106647 seconds.

3 specifications (30 requirements), 0 failures

== Shared contexts

Since version 0.9, you can define shared contexts in test/spec using
shared_context/describe_shared. These contexts are not executed on
their own, but can be included with it_should_behave_like/behaves_like
in other contexts. You can use shared contexts to structure suites
with many recurring specifications.

== Thanks to

  • Eero S. for writing should.output.
  • Tuxie for writing test/spec on Rails.
  • Brian Donovan for allowing alternative superclasses.
  • Xavier S. for implementing nested setups/teardowns.
  • Chris W. for should.raise with a block and xcontext.
  • Jean-Michel Garnier for packaging the first gem.
  • Mikko L., Jan Wikholm, Matt M. and Michael F. for
    testing the gem.
  • Chris McGrath for reporting a bug.
  • Thomas F. for script.aculo.us BDD testing which convinced me.
  • Dave A. for BDD.
  • The RSpec team for API inspiration.
  • Nathaniel T. for Test::Unit.

== Copying

Copyright © 2006, 2007, 2008 Christian N.
test/spec is licensed under the same terms as Ruby itself.

== Where can I get it?

You can download test/spec 0.9 at


Alternatively, you can checkout from the development repository with:

       darcs get http://chneukirchen.org/repos/testspec

Please mail bugs, suggestions and patches to
mailto:[email protected].

(Patches using “darcs send” are most welcome.)

== Installing with RubyGems

Since version 0.3, a Gem of test/spec is available. You can install

gem install test-spec

(It may take some time for the index to be updated and the mirrors
propagated.) I also provide a local mirror of the gems (and
development snapshots) at my site:

gem install test-spec --source http://chneukirchen.org/releases/gems

== Links

Behavior-Driven Development:: http://behaviour-driven.org/
RSpec:: http://rspec.rubyforge.org/
script.aculo.us testing::
FlexMock:: http://onestepback.org/software/flexmock/
Mocha:: http://mocha.rubyforge.org/

Happy hacking and have a nice day,
Christian N.

3fe1bf54cbca0142a9b600992bbcb791f691120f test-spec-0.9.0.tar.gz
f717f1c49d2d28223bbe6a24ac737ae51075bb66 test-spec-0.9.0.gem