minitest-5.0.7 Documentation

# minitest/{unit,spec,mock,benchmark}¶ ↑

home

  github.com/seattlerb/minitest

rdoc

  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::Test
      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/, @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/
        end
      end
    end

For matchers support check out:

github.com/zenspider/minitest-matchers

### Benchmarks¶ ↑

Add benchmarks to your tests.

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

    class TestMeme < Minitest::Benchmark
      # 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. In minitest 5, the describe name needs to match /Bench(mark)?$/.

    describe "Meme Benchmark" 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

## Writing Extensions¶ ↑

To define a plugin, add a file named minitest/XXX_plugin.rb to your project/gem. Minitest will find and require that file using Gem.find_files. It will then try to call plugin_XXX_init during startup. The option processor will also try to call plugin_XXX_options passing the OptionParser instance and the current options hash. This lets you register your own command-line options. Here’s a totally bogus example:

    # minitest/bogus_plugin.rb:

    module Minitest
      def self.plugin_bogus_options(opts, options)
        opts.on "--myci", "Report results to my CI" do
          options[:myci] = true
          options[:myci_addr] = get_myci_addr
          options[:myci_port] = get_myci_port
        end
      end

      def self.plugin_bogus_init(options)
        self.reporter << MyCI.new(options) if options[:myci]
      end
    end

### Adding custom reporters¶ ↑

Minitest uses composite reporter to output test results using multiple reporter instances. You can add new reporters to the composite during the init_plugins phase. As we saw in `plugin_bonus_init` above, you simply add your reporter instance to the composite via +<<+.

`AbstractReporter` defines the API for reporters. You may subclass it and override any method you want to achieve your desired behavior.

start

  Called when the run has started.

record

  Called for each result, passed or otherwise.

report

  Called at the end of the run.

passed?

  Called to see if you detected any problems.

Using our example above, here is how we might implement MyCI:

    # minitest/bogus_plugin.rb

    module Minitest
      class MyCI < AbstractReporter
        attr_accessor :results, :addr, :port

        def initialize options
          self.results = []
          self.addr = options[:myci_addr]
          self.port = options[:myci_port]
        end

        def record result
          self.results << result
        end

        def report
          CI.connect(addr, port).send_results self.results
        end
      end
    end

## 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

### How to share code across test classes?¶ ↑

Use a module. That’s exactly what they’re for:

    module UsefulStuff
      def useful_method
        # ...
      end
    end

    describe Blah do
      include UsefulStuff

      def test_whatever
        # useful_method available here
      end
    end

Remember, `describe` simply creates test classes. It’s just ruby at the end of the day and all your normal Good Ruby Rules (tm) apply. If you want to extend your test using setup/teardown via a module, just make sure you ALWAYS call super. before/after automatically call super for you, so make sure you don’t do it twice.

## Prominent Projects using Minitest:¶ ↑

- arel

- journey

- mime-types

- nokogiri

- rails (active_support et al)

- rake

- rdoc

## 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-filesystem

  Adds assertion and expectation to help testing filesystem contents.

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-line

  Run test at line number

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-expect

  Expect syntax for MiniTest::Spec - expect(sequences).to_include :celery_man

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, and then requiring “minitest/autorun” should automatically pull it in. If not, you’ll need to do it yourself:

    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.