How do i get RSpec's shared examples like behavior in Ruby Test::Unit?

Question

Is there a plugin/extension similar to shared_examples in RSpec for Test::Unit tests?

Arcuation

Answer 1

If you are using rails (or just active_support), use a Concern.

require 'active_support/concern'

module SharedTests
  extend ActiveSupport::Concern

  included do

    # This way, test name can be a string :)
    test 'banana banana banana' do
      assert true
    end

  end
end

If you're not using active_support, just use Module#class_eval.

This technique builds on Andy H.'s answer, where he points out that:

Test::Unit tests are just Ruby classes, so you can use [normal techniques] of code reuse

but because it enables the use of ActiveSupport::Testing::Declarative#test it has the advantage of not wearing out your underscore key :)

Hydrothorax

Answer 2

I was able to implement shared tests (similar to RSpec shared examples) using the following code:

module SharedTests
  def shared_test_for(test_name, &block)
    @@shared_tests ||= {}
    @@shared_tests[test_name] = block
  end

  def shared_test(test_name, scenario, *args)
    define_method "test_#{test_name}_for_#{scenario}" do
      instance_exec *args, &@@shared_tests[test_name]
    end
  end
end

To define and use shared tests in a Test::Unit test:

class BookTest < ActiveSupport::TestCase
  extend SharedTests

  shared_test_for "validate_presence" do |attr_name|
    assert_false Books.new(valid_attrs.merge(attr_name => nil)).valid?
  end

  shared_test "validate_presence", 'foo', :foo
  shared_test "validate_presence", 'bar', :bar
end

Arcuation

Answer 3

Test::Unit tests are just Ruby classes, so you can use the same methods of code reuse as any other Ruby class.

To write shared examples, you could use a module.

module SharedExamplesForAThing
  def test_a_thing_does_something
    ...
  end
end

class ThingTest < Test::Unit::TestCase
  include SharedExamplesForAThing
end

Setiform

Answer 4

require 'minitest/unit'
require 'minitest/spec'
require 'minitest/autorun'

#shared tests in proc/lambda/->
basics = -> do
  describe 'other tests' do
    #override variables if necessary
    before do
      @var  = false
      @var3 = true
    end

    it 'should still make sense' do
      @var.must_equal false
      @var2.must_equal true
      @var3.must_equal true
    end
  end
end

describe 'my tests' do

  before do
    @var = true
    @var2 = true
  end

  it "should make sense" do
    @var.must_equal true
    @var2.must_equal true
  end

  #call shared tests here
  basics.call
end

Sansculotte

Answer 5

Look at this gist I wrote a couple of years ago. It still works great: https://gist.github.com/jodosha/1560208

# adapter_test.rb
require 'test_helper'

shared_examples_for 'An Adapter' do
  describe '#read' do
    # ...
  end
end

Used like this:

# memory_test.rb
require 'test_helper'

describe Memory do
  it_behaves_like 'An Adapter'
end

Casern