A simple and clean mock object framework.

---

Minimal (mostly drop-in) replacement for test-unit.

minitest/{unit,spec,mock,benchmark}

home	github.com/seattlerb/minitest
rdoc	http://docs.seattlerb.org/minitest
vim	github.com/sunaku/vim-ruby-minitest

DESCRIPTION:

minitest provides a complete suite of testing facilities supporting TDD, BDD, mocking, and benchmarking.

"I had a class with Jim Weirich on testing last week and we were
 allowed to choose our testing frameworks. Kirk Haines and I were
 paired up and we cracked open the code for a few test
 frameworks...

 I MUST say that minitest is *very* readable / understandable
 compared to the 'other two' options we looked at. Nicely done and
 thank you for helping us keep our mental sanity."

-- Wayne E. Seguin

minitest/unit is a small and incredibly fast unit testing framework. It provides a rich set of assertions to make your tests clean and readable.

minitest/spec is a functionally complete spec engine. It hooks onto minitest/unit and seamlessly bridges test assertions over to spec expectations.

minitest/benchmark is an awesome way to assert the performance of your algorithms in a repeatable manner. Now you can assert that your newb co-worker doesn’t replace your linear algorithm with an exponential one!

minitest/mock by Steven Baker, is a beautifully tiny mock (and stub) object framework.

minitest/pride shows pride in testing and adds coloring to your test output. I guess it is an example of how to write IO pipes too. :P

minitest/unit is meant to have a clean implementation for language implementors that need a minimal set of methods to bootstrap a working test suite. For example, there is no magic involved for test-case discovery.

"Again, I can't praise enough the idea of a testing/specing
 framework that I can actually read in full in one sitting!"

-- Piotr Szotkowski

Comparing to rspec:

rspec is a testing DSL. minitest is ruby.

-- Adam Hawkins, "Bow Before MiniTest"

minitest doesn’t reinvent anything that ruby already provides, like: classes, modules, inheritance, methods. This means you only have to learn ruby to use minitest and all of your regular OO practices like extract-method refactorings still apply.

FEATURES/PROBLEMS:

• minitest/autorun - the easy and explicit way to run all your tests.

• minitest/unit - a very fast, simple, and clean test system.

• minitest/spec - a very fast, simple, and clean spec system.

• minitest/mock - a simple and clean mock/stub system.

• minitest/benchmark - an awesome way to assert your algorithm’s performance.

• minitest/pride - show your pride in testing!

• Incredibly small and fast runner, but no bells and whistles.

RATIONALE:

See design_rationale.rb to see how specs and tests work in minitest.

SYNOPSIS:

Given that you’d like to test the following class:

class Meme
  def i_can_has_cheezburger?
    "OHAI!"
  end

  def will_it_blend?
    "YES!"
  end
end

Unit tests

require 'minitest/autorun'

class TestMeme < MiniTest::Unit::TestCase
  def setup
    @meme = Meme.new
  end

  def test_that_kitty_can_eat
    assert_equal "OHAI!", @meme.i_can_has_cheezburger?
  end

  def test_that_it_will_not_blend
    refute_match /^no/i, @meme.will_it_blend?
  end

  def test_that_will_be_skipped
    skip "test this later"
  end
end

Specs

require 'minitest/autorun'

describe Meme do
  before do
    @meme = Meme.new
  end

  describe "when asked about cheeseburgers" do
    it "must respond positively" do
      @meme.i_can_has_cheezburger?.must_equal "OHAI!"
    end
  end

  describe "when asked about blending possibilities" do
    it "won't say no" do
      @meme.will_it_blend?.wont_match /^no/i
    end
  end
end

For matchers support check out:

github.com/zenspider/minitest-matchers

Benchmarks

Add benchmarks to your regular unit tests. If the unit tests fail, the benchmarks won’t run.

# optionally run benchmarks, good for CI-only work!
require 'minitest/benchmark' if ENV["BENCH"]

class TestMeme < MiniTest::Unit::TestCase
  # Override self.bench_range or default range is [1, 10, 100, 1_000, 10_000]
  def bench_my_algorithm
    assert_performance_linear 0.9999 do |n| # n is a range value
      @obj.my_algorithm(n)
    end
  end
end

Or add them to your specs. If you make benchmarks optional, you’ll need to wrap your benchmarks in a conditional since the methods won’t be defined.

describe Meme do
  if ENV["BENCH"] then
    bench_performance_linear "my_algorithm", 0.9999 do |n|
      100.times do
        @obj.my_algorithm(n)
      end
    end
  end
end

outputs something like:

# Running benchmarks:

TestBlah    100     1000    10000
bench_my_algorithm   0.006167        0.079279        0.786993
bench_other_algorithm        0.061679        0.792797        7.869932

Output is tab-delimited to make it easy to paste into a spreadsheet.

Mocks

class MemeAsker
  def initialize(meme)
    @meme = meme
  end

  def ask(question)
    method = question.tr(" ","_") + "?"
    @meme.__send__(method)
  end
end

require 'minitest/autorun'

describe MemeAsker do
  before do
    @meme = MiniTest::Mock.new
    @meme_asker = MemeAsker.new @meme
  end

  describe "#ask" do
    describe "when passed an unpunctuated question" do
      it "should invoke the appropriate predicate method on the meme" do
        @meme.expect :will_it_blend?, :return_value
        @meme_asker.ask "will it blend"
        @meme.verify
      end
    end
  end
end

Stubs

def test_stale_eh
  obj_under_test = Something.new

  refute obj_under_test.stale?

  Time.stub :now, Time.at(0) do   # stub goes away once the block is done
    assert obj_under_test.stale?
  end
end

A note on stubbing: In order to stub a method, the method must actually exist prior to stubbing. Use a singleton method to create a new non-existing method:

def obj_under_test.fake_method
  ...
end

Customizable Test Runner Types:

MiniTest::Unit.runner=(runner) provides an easy way of creating custom test runners for specialized needs. Justin Weiss provides the following real-world example to create an alternative to regular fixture loading:

class MiniTestWithHooks::Unit < MiniTest::Unit
  def before_suites
  end

  def after_suites
  end

  def _run_suites(suites, type)
    begin
      before_suites
      super(suites, type)
    ensure
      after_suites
    end
  end

  def _run_suite(suite, type)
    begin
      suite.before_suite
      super(suite, type)
    ensure
      suite.after_suite
    end
  end
end

module MiniTestWithTransactions
  class Unit < MiniTestWithHooks::Unit
    include TestSetupHelper

    def before_suites
      super
      setup_nested_transactions
      # load any data we want available for all tests
    end

    def after_suites
      teardown_nested_transactions
      super
    end
  end
end

MiniTest::Unit.runner = MiniTestWithTransactions::Unit.new

FAQ

How to test SimpleDelegates?

The following implementation and test:

class Worker < SimpleDelegator
  def work
  end
end

describe Worker do
  before do
    @worker = Worker.new(Object.new)
  end

  it "must respond to work" do
    @worker.must_respond_to :work
  end
end

outputs a failure:

  1) Failure:
Worker#test_0001_must respond to work [bug11.rb:16]:
Expected #<Object:0x007f9e7184f0a0> (Object) to respond to #work.

Worker is a SimpleDelegate which in 1.9+ is a subclass of BasicObject. Expectations are put on Object (one level down) so the Worker (SimpleDelegate) hits `method_missing` and delegates down to the `Object.new` instance. That object doesn’t respond to work so the test fails.

You can bypass `SimpleDelegate#method_missing` by extending the worker with `MiniTest::Expectations`. You can either do that in your setup at the instance level, like:

before do
  @worker = Worker.new(Object.new)
  @worker.extend MiniTest::Expectations
end

or you can extend the Worker class (within the test file!), like:

class Worker
  include ::MiniTest::Expectations
end

Known Extensions:

capybara_minitest_spec	Bridge between Capybara RSpec matchers and MiniTest::Spec expectations (e.g. page.must_have_content(‘Title’)).
minispec-metadata	Metadata for describe/it blocks (e.g. `it ‘requires JS driver’, js: true do`)
minitest-ansi	Colorize minitest output with ANSI colors.
minitest-around	Around block for minitest. An alternative to setup/teardown dance.
minitest-capistrano	Assertions and expectations for testing Capistrano recipes
minitest-capybara	Capybara matchers support for minitest unit and spec
minitest-chef-handler	Run Minitest suites as Chef report handlers
minitest-ci	CI reporter plugin for MiniTest.
minitest-colorize	Colorize MiniTest output and show failing tests instantly.
minitest-context	Defines contexts for code reuse in MiniTest specs that share common expectations.
minitest-debugger	Wraps assert so failed assertions drop into the ruby debugger.
minitest-display	Patches MiniTest to allow for an easily configurable output.
minitest-emoji	Print out emoji for your test passes, fails, and skips.
minitest-english	Semantically symmetric aliases for assertions and expectations.
minitest-excludes	Clean API for excluding certain tests you don’t want to run under certain conditions.
minitest-firemock	Makes your MiniTest mocks more resilient.
minitest-great_expectations	Generally useful additions to minitest’s assertions and expectations
minitest-growl	Test notifier for minitest via growl.
minitest-implicit-subject	Implicit declaration of the test subject.
minitest-instrument	Instrument ActiveSupport::Notifications when test method is executed
minitest-instrument-db	Store information about speed of test execution provided by minitest-instrument in database
minitest-libnotify	Test notifier for minitest via libnotify.
minitest-macruby	Provides extensions to minitest for macruby UI testing.
minitest-matchers	Adds support for RSpec-style matchers to minitest.
minitest-metadata	Annotate tests with metadata (key-value).
minitest-mongoid	Mongoid assertion matchers for MiniTest
minitest-must_not	Provides must_not as an alias for wont in MiniTest
minitest-nc	Test notifier for minitest via Mountain Lion’s Notification Center
minitest-predicates	Adds support for .predicate? methods
minitest-rails	MiniTest integration for Rails 3.x
minitest-rails-capybara	Capybara integration for MiniTest::Rails
minitest-reporters	Create customizable MiniTest output formats
minitest-should_syntax	RSpec-style +x.should == y+ assertions for MiniTest
minitest-shouldify	Adding all manner of shoulds to MiniTest (bad idea)
minitest-spec-context	Provides rspec-ish context method to MiniTest::Spec
minitest-spec-magic	Minitest::Spec extensions for Rails and beyond
minitest-spec-rails	Drop in MiniTest::Spec superclass for ActiveSupport::TestCase.
minitest-stub-const	Stub constants for the duration of a block
minitest-tags	add tags for minitest
minitest-wscolor	Yet another test colorizer.
minitest_owrapper	Get tests results as a TestResult object.
minitest_should	Shoulda style syntax for minitest test::unit.
minitest_tu_shim	minitest_tu_shim bridges between test/unit and minitest.
mongoid-minitest	MiniTest matchers for Mongoid.
pry-rescue	A pry plugin w/ minitest support. See pry-rescue/minitest.rb.

Unknown Extensions:

Authors… Please send me a pull request with a description of your minitest extension.

• assay-minitest

• detroit-minitest

• em-minitest-spec

• flexmock-minitest

• guard-minitest

• guard-minitest-decisiv

• minitest-activemodel

• minitest-ar-assertions

• minitest-capybara-unit

• minitest-colorer

• minitest-deluxe

• minitest-extra-assertions

• minitest-rails-shoulda

• minitest-spec

• minitest-spec-should

• minitest-sugar

• minitest_should

• mongoid-minitest

• spork-minitest

REQUIREMENTS:

• Ruby 1.8, maybe even 1.6 or lower. No magic is involved.

INSTALL:

sudo gem install minitest

On 1.9, you already have it. To get newer candy you can still install the gem, but you’ll need to activate the gem explicitly to use it:

require 'rubygems'
gem 'minitest' # ensures you're using the gem, and not the built in MT
require 'minitest/autorun'

# ... usual testing stuffs ...

DO NOTE: There is a serious problem with the way that ruby 1.9/2.0 packages their own gems. They install a gem specification file, but don’t install the gem contents in the gem path. This messes up Gem.find_files and many other things (gem which, gem contents, etc).

Just install minitest as a gem for real and you’ll be happier.

LICENSE:

(The MIT License)

Copyright © Ryan Davis, seattle.rb

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the ‘Software’), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED ‘AS IS’, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

lib/minitest/unit.rb
lib/minitest/mock.rb
lib/test/unit.rb