Minitest

Minitest real test examples: openstreetmap, redmine

Mini test for rails TestCases (for example ActiveSupport::TestCase) inherits from Minitest::Test so you can use it def test_method, but Rails adds test method so it can be used like test "my method" do. In minitests you can not have same test descriptions since it will be converted to same test_my_method.

You can run specific test with :10 or -n test_name. If test is defined like test "my test" than you can use regexp ruby test/file_test.rb -n /my.test/ This also works for system test (so you do not need system in rails test:system somefile)

rails test
rails test:system
# invoke test by line
rails test test/models/article_test.rb:6
# or name
# works only when you use `def test_example` syntax
# for `test "test_example" do` you should use -n test_test_example
rails test -n test_example

You could also use ENV variables rails test TEST=test/machine_with_callbacks_test.rb TESTOPTS="--name=test_should_run_validations_for_specific_state -v"

Each test run will load all fixture data, run setup blocks, run test method, run teardown block, rollback fixtures.

Fixtures

http://api.rubyonrails.org/v5.2.0/classes/ActiveRecord/FixtureSet.html

Rails performs loading fixtures in tree steps: removing old fixture data, load fixture data and dump data into a method inside test case users(:david) Note that when using smoke: Yes or smoke: No it might be converted to true false, so better is to use smoke: 'Yes' or smoke: 'No'

Defining fixtures:

• use labels for associated belongs_to and has_many items (separated by comma)

  # test/fixtures/users.yml
  my_user:
    name: My User
    company: my_company
  
  # test/fixtures/companies.yml
  my_company:
    name: My Company
  

• if you have polymorphic than put class name in brackets

  # test/fixtures/notifications.yml
  notification_for_task:
    notifiable: my_task (Task)
  notification_for_comment:
    notifiable: my_comment (Comment)
  

  No need to use brackets if you have belongs_to :associated, class_name: 'Activity'

• for activestorage attachments you do not need to create fake models. just create real fixtures https://stackoverflow.com/questions/50453596/activestorage-fixtures-attachments When I skip key not null column in fixture than I receive strange errors

  /home/orlovic/.rvm/rubies/ruby-2.6.3/lib/ruby/2.6.0/drb/drb.rb:565:in `dump': no _dump_data is defined for class PG::Connection (TypeError)
  /home/orlovic/.rvm/rubies/ruby-2.6.3/lib/ruby/2.6.0/drb/drb.rb:565:in `dump': can't dump hash with default proc (TypeError)
  # those are just backtrace errors for runners, not important, messages before
  # this are more important
  /home/orlovic/.rvm/rubies/ruby-2.6.3/lib/ruby/2.6.0/drb/drb.rb:1738:in `current_server': DRb::DRbServerNotFound (DRb::DRbServerNotFound)
  /home/orlovic/.rvm/gems/ruby-2.6.3/gems/activesupport-6.0.2.1/lib/active_support/testing/parallelization.rb:98:in `block (3 levels) in start': undefined method `exception=' for #<Minitest::UnexpectedError: Unexpected exception> (NoMethodError)
  

  Here are fixtures so you have some blobs in db (another way to test is using fixture_file_upload)

  # test/fixtures/active_storage/blobs.yml
  my_blob:
    key: or9sbwfely5gby30qdvtoa1cu09a
    filename: computer_text.png
    content_type: image/png
    # jsonb
    metadata: '{"identified":true}'
    metadata: <%= { "identified" => true }.to_json %>
    byte_size: 56024
    checksum: wHaMfHXpSThHCX/zvm5fFg==
  
  # test/fixtures/active_storage/attachments.yml
  DEFAULTS: &DEFAULTS
    # you can use same fake blob for all attachments
    blob_id: <%= ActiveRecord::FixtureSet.identify(:my_blob) %>
    created_at: 2019-12-06
  
  my_attachment:
    <<: *DEFAULTS
    <%# this has to be the same name as in has_one_attached %>
    name: file
    record: my_doc (Doc)
    <%# record_type: Doc %>
    <%# record_id: <%= ActiveRecord::FixtureSet.identify(:my_doc) %1> %>
  

  If you want to have real file for this blobs, you can use before(:all) setup before whole suite, to copy file to appropriate location so seed from fixtures can be used on developing

  # test/test_helper.rb
    def self.initialize_fixture_blob
      return if File.exist? "#{Rails.root}/tmp/storage/or/9s/or9sbwfely5gby30qdvtoa1cu09a"
  
      FileUtils.mkdir_p "#{Rails.root}/tmp/storage/or/9s"
      FileUtils.cp(
        "#{Rails.root}/test/fixtures/files/computer_text.png",
        "#{Rails.root}/tmp/storage/or/9s/or9sbwfely5gby30qdvtoa1cu09a"
      )
    end
    initialize_fixture_blob
  

  To use in request use blob.signed_id

  test 'upload one picture' do
    user = users(:user)
    attachment = user.member_profile.member_picture.active_storage_attachment
    sign_in user
  
    blob = attachment.blob.signed_id
    assert_difference 'ActiveStorage::Blob.count', 0 do
      assert_difference 'MemberPicture.count', 1 do
        patch profile_update_path, params: { member_profile: { id: user.member_profile, member_pictures_attributes: { '0' => { active_storage_attachment: blob } } } }
        assert_response :redirect
      end
    end
  end
  

  File upload from test/fixtures/files/logo.png https://apidock.com/rails/ActionDispatch/TestProcess/FixtureFile/fixture_file_upload

  # include if not fixture_file_upload is not available
  
  include ActionDispatch::TestProcess # for fixture_file_upload
  
  post :create, logo: fixture_file_upload('files/logo.png', 'image/png')
  

• enum parent_relations: %i[child] can be set using erb

  child:
    parent_relation: <%= User.parent_relations[:child] %>
  

• created_at, updated_at, created_on and updated_on is automatically Time.now
• use ERB for dynamic creation. Note that you should use fixed dates instead of published_at: <%= Date.today.strftime('%Y-%m-%d') so they are stable. Note that erb is evaluated before yml (for example $LABEL)

  <% 15.times do |i| %>
  medium_<%= i %>:
    media_name: My <%= i %> Medium
    published_at: 2018-10-11
  <% end %>
  

• fixture label interpolation ($LABEL is me)

  me:
    name: 'duke'
    subdomain: me
    # or use label
    subdomain: $LABEL
    email: [email protected]
  

  $Label is not interpolated within object like name: { en: $LABEL } (so I18n mobility does not work)

• defaults

  DEFAULTS: &DEFAULTS
    name: $LABEL Name
    created_on: <%= 3.weeks.ago.to_s(:db) %>
  
  first:
    name: Smurf
    <<: *DEFAULTS
  
  second:
    name: Fraggle
    <<: *DEFAULTS
  

• if you really want hardcoded ids you can use

  my_language:
    id: 5
    name: English
  
  course:
    language_id: 5
    # note that this is just yml so you can not use
    language_id: my_language.id
    # but you can use erb
    language_id: <%= ActiveRecord::FixtureSet.identify :my_language %>
  

• pre_loaded_fixtures

• use_transactional_tests. In Rails 4 it was use_transactional_fixtures but since it could be factories not fixtures, that is renamed to use_transactional_tests. So to disable it you can use

  class FooTest < ActiveSupport::TestCase
    self.use_transactional_tests = false
  end
  

• when defining new fixtures, add them to the end, so you do not break current test for first page (when you use pagination)
• load fixtures in development rake db:fixtures:load so put in your seed
• to set devise password, you can add encrypted password on specific items

  admin_user:
    encrypted_password: <%= User.new.send(:password_digest, 'password') %>
  
  # without device it is with gem bcrypt
    password_digest: <%= BCrypt::Password.create('password') %>
  

• if you use serialize :recurrence than in fixture you have to wrap with double quotes around and use .to_yaml

  recurrence: "<%= { a: 1 }.toyaml %>"
  

• if there are no colomns you can use user: {} curly brackets

• Usage of fixtures

  # note that we are calling method users()
  users(:my_user)
  # we can get two
  users(:duke, mike)
  

• do not need to put all data in fixtures, you can create simple factories

  # test/models/user_test.rb
  require 'test_helper'
  
  class UserTest < ActiveSupport::TestCase
    def create_user!(attr = {})
      user = users(:user).dup
      user.email = "#{rand}@email.com"
      user.password = "password"
      user.assign_attributes attr
      user.save!
      user
    end
  
    test "all users" do
    def test_example
      users = []
      users.append create_user!
      users.append create_user! unsubscribe_email_groups: ["remainders"]
      users.append create_user! unsubscribe_email_groups: ["messages"]
  
      assert_emails 2 do
        result = WeeklyRemainderWorker.new.perform(users)
        assert result.success?
      end
    end
  end
  

Minitest classes

To see all 6 base test clases go http://guides.rubyonrails.org/testing.html#a-brief-note-about-test-cases ActiveSupport::TestCase ActionMailer::TestCase ActionView::TestCase ActionDispatch::IntegrationTest ActiveJob::TestCase ActionDispatch::SystemTestCase

Minitest model

require 'test_helper'

class TaskTest < ActiveSupport::TestCase
  test 'a completed' do
    task = Task.new
    refute(task.complete?)
    task.mark_completed
    assert(task.complete?)
  end

  def test_that_is_skipped
    skip "later"
    # similar to xtest xit
  end

  test 'valid fixture' do
    assert_valid_fixture activities
  end

  # test/test_helper.rb
  def assert_valid_fixture(items)
    assert items.map(&:valid?).all?, (items.reject(&:valid?).map { |c| (c.respond_to?(:name) ? "#{c.name} " : '') + c.errors.full_messages.to_sentence })
  end
end

Assertions all

• assert true or assert_block do end
• assert_nil
• assert_empty
• assert_raises(NameError) do end
• assert_match regex, actual_string
• assert_includes(collection, object)
• assert_equal(expected, actual)

They all have oposite refute_ methods, or assert_not They all accept additional string param that will be error message.

http://guides.rubyonrails.org/testing.html#rails-specific-assertions Rails also defines assert_difference, assert_empty, assert_presence, assert_response, assert_redirected_to, assert_select (assert select for custom html text is done with additional argument) https://stackoverflow.com/questions/4739261/is-there-a-way-to-use-assert-select-on-some-custom-html-text

    doc = HTML::Document.new(CGI::unescapeHTML(extracted_text)).root
    assert_select(doc, tag, content)

You can create your own assertiongs (assert sorted) Reopen module MiniTest::Assertions when helper is used in all tests. If you need only for system tests (assert_selector) or integration test (assert_select) than you need to reopen that particular class https://github.com/duleorlovic/premesti.se/blob/master/test/support/assert_equal_when_sorted_by_id.rb

# test/a/assert_flash_message.rb
# https://github.com/duleorlovic/minitest_rails/blob/main/test/a/assert_flash_message.rb
class ActionDispatch::IntegrationTest
  # assert_flash_message
  def assert_alert_message(text)
    assert_select '[data-test=alert]', text
  end

  def assert_notice_message(text)
    assert_select '[data-test=notice]', text
  end
end

class ActionDispatch::SystemTestCase
  def assert_alert_message(text)
    assert_selector '[data-test=alert]', text: text
  end

  def assert_notice_message(text)
    assert_selector '[data-test=notice]', text: text
  end
end

For any method? you can assert for example

assert_kind_of Array, exp

Minitest services

Similar to model test you can create tests for services since there are PORO

# test/services/credit_card_service_test.rb
require 'test_helper'

class CreditCardServiceTest < ActiveSupport::TestCase
  test 'it creates charges' do
  end
end

VCR

To install use

# Gemfile
group :test do
  gem 'vcr'
  gem 'webmock'
end

# test/a/vcr.rb
VCR.configure do |config|
  config.cassette_library_dir = 'test/vcr_cassettes'
  config.hook_into :webmock
  config.ignore_localhost = true
end

# test/services/my_service_test.rb
require 'test_helper'

class MyServiceTest < ActiveSupport::TestCase
  test 'success' do
    VCR.use_cassette 'my_service' do
      result = MyService.new(users(:my)).perform
      assert result.success?
    end
  end

  # you could also use in setup and teardown
  # https://github.com/vcr/vcr/wiki/Usage-with-MiniTest
   before do
      VCR.insert_cassette name
    end

    after do
      VCR.eject_cassette
    end
  end

Also works for system test, just I need to retry with delay for long processes (you can simulate by inserting sleep 5 in your service).

# test/system/docs_test.rb
require 'application_system_test_case'

class DocsTest < ApplicationSystemTestCase
  test 'creating a Doc' do
    VCR.use_cassette 'detect_text_and_phi_computer_text' do
      visit docs_url
      click_on t_crud('add_new', Doc)

      fill_in 'Name', with: @doc.name
      page.attach_file 'doc[file]', "#{Rails.root}/test/fixtures/files/computer_text.png", make_visible: true
      click_on 'Create Doc'

      retries = 5
      begin
        retries -= 1
        assert_notice 'Doc successfully created'
      rescue Minitest::Assertion => e
        puts "retries=#{retries}"
        raise e if retries.zero?

        sleep 1
        retry
      end
    end
  end
end

More info on rails testing page

Minitest controllers

Deprecated, use minitest integration tests

Minitest integration

For integration we use ActionDispatch::IntegrationTest which gives methods:

• get '/', post path, params: {} (params is required in rails_post_5), To set format use patch path, params: { format: :turbo_stream }
• also put, patch, head, delete
• for ajax use post path, xhr: true
• add as: :json as third param for json requests so you can use something like

  get article_path(@article), as: :json
  assert_equal "my title", response.parsed_body["title"]
  

• follow_redirect!
• assert_redirected_to post_url(Post.last),or you can match only part of url using @response object

   assert_match /https:\/\/www.myapp.com\/path/, @response.redirect_url
  

• assert_response :success (for http codes 200-299), :redirect (300-399), :missing (404), :error (500-599).
• assert_select 'h1', user.email . Note that white spaces and new lines are ignored
• assert_difference 'User.count', 1 do
• You have access to @request, @controller and @response object, but only after you call get, post. You can set request.remote_ip by passing headers (note that http referrer is written as http referer (single r)

  get sign_up_path, params: { user: { email: '[email protected]' } }, headers: { 'REMOTE_ADDR': '123.123.123.123', HTTP_REFERER: 'http://domain.com', 'HTTP_USER_AGENT': 'Mozilla'}
  

  also you can authenticate basic auth

  get my_path, headers: { Authorization: ActionController::HttpAuthentication::Basic.encode_credentials('dhh', 'secret') }
  

• to change default host you can use setup block (similar to rspec before) in test helper

  # test/test_helper.rb
  class ActiveSupport::TestCase
    def setup
      host! 'example.com'
    end
  end
  

• assert_select 'h1', 'Welcome' is used to test view. View can be tested with assert_match /Welcome/', response.body, for multi line you can use /m assert_match /first line.*second line/m, response.body refute_match "Welcome", response.body to assert not included text There are two forms of assert_select selector, [equality], [message] or using Nokogiri::XML::Node as element assert_select element, selector, [equality]. selector can be CSS selector as one string, or array with substitutions

  assert_select 'div#123' # exists <div id='123'>
  assert_select "a[href='http://www.example.com/diary/new']"
  assert_select 'a[href=?]', tasks_path
  assert_select 'input[value=?]', username   # substitute username
  assert_select 'input[value*=?]', username   # match when containing username
  assert_select '[data-test=unread-count]', count: 123
  assert_select '[data-test=unread-count]', minimum: 123
  
  # use custom pseudo class `:match(attribute_name, attribute_value)`
  assert_select "ol>li:match('id', ?)", /item-\d+/       # exists li id='item-1'
  assert_select "div:match('id',?)", /\d+/        # exists div with non empty id
  
  assert_select 'div', 'Hello' # exists <div>Hello</div>
  assert_select 'div', /hello/ # if div text matches
  assert_select 'div', false # no divs exists
  assert_select 'div', 4 # exactly 4 divs
  assert_select 'div', 4..5 # number of dives is in range
  
  # multiple attributes
  assert_select "input[type=checkbox][value=messages][checked=checked]", 1
  

  To perform more than one quality tests in one assert you can use hash (assert_selector also use this hash param, like presence items assert_selector '[data-test^=member-profile-]', count: Const.limits[:per_page])

  # instead of refute_select, for no div with my_name you can use count but put
  # inside hash: text: and count:
  assert_select 'a[href=?]', 'http://link.com', text: /my_name/, count: 0
  # https://apidock.com/rails/ActionController/Assertions/SelectorAssertions/assert_select
   # All input fields in the form have a name
  assert_select "form input" do
    assert_select "[name=?]", /.+/  # Not empty
  end
  
  # https://apidock.com/rails/HTML/Selector
  # to target all elements data-test="member-profile-1", data-test="member-profile-2"
  assert_select '[data-test^=member-profile-]', 10
  
  # not sure how to use substitution, why this does not work
  assert_select '[data-test=member-profile-?]', /.+/, count: 10
  
  assert_select 'div', html: 'p', minimum: 2
  

  Error like

  Nokogiri::CSS::SyntaxError: unexpected '$' after '[:equal, "id-1"]'
    (eval):3:in `_racc_do_parse_c'
    (eval):3:in `do_parse'
  

  occurs when you forget closing brackets assert_selector '[data-test=id-1'

  To check html in emails use assert_select_email

  assert_select_email do
    items = assert_select "ol>li"
    items.each do
      Work with items here...
    end
  end
  

Those integration tests are similar to Rspec request spec, and works full stack with no use of capybara. More info https://github.com/rails/rails-dom-testing/blob/master/lib/rails/dom/testing/assertions/selector_assertions.rb similar to capybara have_selector but separate implementation html selector. http://www.rubydoc.info/github/rails/rails-dom-testing/Rails%2FDom%2FTesting%2FAssertions%2FSelectorAssertions%3Aassert_select After request is made you can also access @controller, @request and @response (same as response).

# test/controllers/projects_controller_test.rb
require 'test_helper'

class ProjectsControllerTest < ActionDispatch::IntegrationTest
  setup do
    @project = create :project
  end

  # called after every single test
  teardown do
    # when controller is using cache it may be a good idea to reset it afterwards
    Rails.cache.clear
  end

  test 'show' do
    get project_path(@project)
    assert_select "#tutorial-#{tutorials(:priced_course_first_free_tutorial).id}", /Watch this lesson now/
    assert_select "#tutorial-#{tutorials(:priced_course_third_tutorial).id}", text: /Watch this lesson now/, count: 0

    # or you can parse `response.body` do it manually

    doc = Nokogiri::HTML response.body
    # you can get all respone text with doc.text.split.join(' ')
    el = doc.search "#tutorial-#{tutorials(:priced_course_first_free_tutorial).id}"
    assert_match 'Watch this lesson now', el.text
    el = doc.search "#tutorial-#{tutorials(:priced_course_third_tutorial).id}"
    assert_no_match 'Watch this lesson now', el.text
  end

  test "the create method creates project" do
    post projects_url, params: { project: { name: 'Duke' } }
    assert_redirected_to projects_path
    # also available: assert_response :redirect
    follow_redirect!
    assert_select '#my-id', /dule/
  end
end

Minitest routing

It uses assert_routing.

Minitest helper

Uses assert_dom_equal

# test/helpers/projects_helper_test.rb
require 'test_helper'
class ProjectsHelperTest < ActionView::TestCase
  test "project on schedule" do
    project = Project.new name: 'Duke'
    project.stubs(:on_schedule?).returns(true)
    actual= name_with_status(project)
    expected = "<span class='on-schedule'>Duke</span>"
    assert_dom_equal expected, actual
  end
end

Minitest system

Feature tests are run in different process than rails so we need database cleaner gem. With system tests, we can use internal mechanism to roll back db changes. Before we used feature specs for full application integration testing, but now we should use system specs (which also uses capybara and webdriver with chrome). Add to gemfile

  # system test
  gem 'capybara' # 3.35.3
  gem 'selenium-webdriver' # 3.142.7

and create

# test/application_system_test_case.rb
require 'test_helper'

class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
  # driven_by :selenium, using: :headless_chrome, screen_size: [1400, 1400]
  driven_by :selenium, using: :chrome, screen_size: [1400, 1400]

  # you can use bye bug, but it will stop rails so you can not navigate to other
  # pages or make another requests in chrome while testing
  def pause
    $stderr.write('Press CTRL+j or ENTER to continue') && $stdin.gets
  end
end

Use nameing like ROLE_ACTION_test.rb for example user_shares_card_test.rb

System tests are not included in default test suite if you run rails test (you should run rake test:system), but if you run specific test than it will be run rails test test/system/my_test.rb.

Note that if you use puma with multiple workers than ActionMailer::Base.deliveries.size could be different in rails process and in test process, so use workers 0 in config/puma/test.rb. Or insclude ActionMailer::TestHelper and use assert_emails method.

To limit number of bowsers (default is number of cores) use

PARALLEL_WORKERS=1 rails test:system

In system test you can’t mock OmniAuth.mock_auth so use integration test for that.

Capybara assertions http://www.rubydoc.info/gems/capybara/Capybara/Minitest/Assertions

• assert_text /dule/ or assert_text Regexp.new('dule', Regexp::MULTILINE) (instead of assert_match /dule/, page.body or in rspec expect(page).to include 'dule'
• assert_selector 'a', text: 'duke' you can assert other html attributes with square brackets

   assert_selector '#my_id[readonly="readonly"][value="My Name"]'
  

  or if you use find.attribute

   assert_match "avatar_female4", find('[data-test="profile-image"]').native.attribute("src")
  

• assert_equal admin_path, page.current_path page.url ie page.current_url contains also http:// so better is to use page path

Webmock

# Gemfile
gem 'webmock'

# config/initializers/webmock.rb
if Rails.env.test?
  require 'webmock'
  # https://github.com/titusfortner/webdrivers/issues/109
  driver_urls = Webdrivers::Common.subclasses.map do |driver|
    Addressable::URI.parse(driver.base_url).host
  end
  WebMock.disable_net_connect!(allow_localhost: true, allow: driver_urls)
  WebMock.disable_net_connect!(allow_localhost: true)
end

# test/test_helper.rb
require 'webmock/minitest'

Minitest helpers

Add a line in test/test_helper.rb to include files from test/a

# test/test_helper.rb
ENV['RAILS_ENV'] ||= 'test'
require File.expand_path('../../config/environment', __FILE__)
Dir[Rails.root.join('test/a/**/*.rb')].each { |f| require f }
require 'rails/test_help'
require 'minitest/autorun'
require 'webmock/minitest'

class ActiveSupport::TestCase
  # create(:user) instead FactoryBot.create :user
  include FactoryBot::Syntax::Methods

  # stub_something
  include WebmockHelper.

  # t('successfully') instead I18n.t('successfully')
  include AbstractController::Translation

  # devise method: sign_in user
  include Devise::Test::IntegrationHelpers

  # Setup all fixtures in test/fixtures/*.yml for all tests in alphabetical order.
  fixtures :all

  # assert_emails 1
  include ActionMailer::TestHelper

end

# test/a/webmock_helper.rb
module WebmockHelpers
  def stub_s3
    stub_request(:get, /s3.amazonaws.com/).to_return(status: 200, body: 'text')
    yield if block_given?
  end

  def stub_ip_info(timezone)
    stub_request(:get, /ipinfo.io/)
      .to_return(headers: {content_type: 'application/json'}, body: {"timezone": timezone}.to_json)
  end
end

I prefer to use factories on specific integration test so when I need to remove specific fixtures I use rails Courses.delete_all. I do not use database cleaner because it complicates thinks because I need to load some specific fixtures (like users) and remove other. Not sure if that will remove fixtures for other tests https://stackoverflow.com/a/28539464/287166

For pause

# test/a/pause_helper.rb
module PauseHelper
  # you can use byebug, but it will stop rails so you can not navigate to other
  # pages or make another requests in chrome while testing
  def pause
    $stderr.write('Press CTRL+j or ENTER to continue') && $stdin.gets
  end
end

class ActionDispatch::SystemTestCase
  include PauseHelper
end

Minitest Mock

You need to require autorun

# test/test_helper.rb
require 'minitest/autorun'

http://ruby-doc.org/stdlib-2.0.0/libdoc/minitest/rdoc/MiniTest/Mock.html

You can mock return values:

@mock = Minitest::Mock.new
@mock.expect(:meaning_of_life, 42)
@mock.meaning_of_life # => 42

and also for arguments and verify their type or value

@mock.expect(:do_something_with, true, [some_obj, true])
@mock.do_something_with(some_obj, true) # => true

@mock.expect(:uses_any_string, true, [String])
@mock.uses_any_string("foo") # => true
@mock.verify  # => true

@mock.expect(:uses_one_string, true, ["foo"]
@mock.uses_one_string("bar") # => true
@mock.verify  # => raises MockExpectationError

You can use Object.stub https://github.com/seattlerb/minitest#stubs https://github.com/seattlerb/minitest#mocks https://stackoverflow.com/questions/10990622/how-do-i-stub-a-method-to-raise-an-error-using-ruby-minitest

require "minitest/autorun"

class MyModel
  def my_method; end
end

class TestRaiseException < MiniTest::Unit::TestCase
  def test_raise_exception
    my_instance = MyModel.new
    raises_exception = Proc.new { raise ArgumentError, 'hi' }
    my_instance.stub :my_method, raises_exception do
      e = assert_raises(ArgumentError) { my_instance.my_method }
      assert_equal 'hi', e.message
    end
  end
end

Stub works also with some custom doubles mock. You can define singleton method on mock def mock.apply; end but can not use other methods or variables… in this case use mock.expect :method, return_value

# test/models/user_test.rb
require 'test_helper'
class UserTest < ActiveSupport::TestCase
  test '#apply_subscription' do
    mock = Minitest::Mock.new
    def mock.apply; true; end
    # or
    mock.expect :apply, true

    SubscriptionService.stub :new, mock do
      user = users(:one)
      assert user.apply_subscription
    end
  end
end

Minitest mocha feature tests

Rails calls “integration tests” as “request tests” and it covers both controller and view code. If logic is more complex, it should be written in model anyway, and use lower level tests.

With capybara:

# Gemfile
  gem "minitest-rails-capybara"
  gem "mocha", require: false

# test/test_helper.rb
require "minitest/rails/capybara"
require "mocha/mini_test"

  test "full double" do
    stubby = stub(name: "Dule", wight: 100)
    assert_equal("Dule", stubby.name)
  end

  test "verifying double" do
    stubby = stub(name: "Dule", weight: 100)
    stubby.responds_like(Project.new)
    # or
    stubby.responds_like_instance_of(Project)
    # this is find since project.name exists
    stubby.name
    # this will raise error
    skip
    stubby.weight
  end

  test "partial double" do
    project = Project.new name: 'Dule'
    # we can stub method on any ruby object
    project.stubs(:name)
    # returns nothing unless we use returns
    assert_nil(project.name)
    # we can stub non existing methods
    project.stubs(:asd)
    assert_nil(project.asd)
    # we can define return
    project.stubs(:due_date).returns(Date.today)
    assert_equal(project.due_date, Date.today)
    # we can stub classes
    Project.stubs(:find).returns(Project.new(name: 'dule'))
    project = Projet.find(1)
    assert_equal('dule', project.name)
    # we can stub any instance
    Project.any_instance.stubs(:save).returns(false)
  end

  test "mock expectation" do
    mock_project = Project.new name: 'Not important since expect returns'
    mock_project.expects(:name).returns('Duke')
    # previous expectation will fail if we have not called it
    assert_equal('Duke', mock_project.name)
    # we can set number of times it is called
    mock_project.expects(:name).twice
    mock_project.name
    mock_project.name
    # we can set arguments
    mock_task = Task.new
    mock_task.expects(:mark_as_completed).with(instance_of(Date)).returns(instance_of(Date))
    mock_task.mark_as_completed Date.today
    mock_task.expects(:mark_as_completed).with(instance_of(String)).returns(nil)
    mock_task.mark_as_completed "bla"
  end

Guard

For guard minitest use guard-minitest

sed -i Gemfile -e '/group :development do/a  \
  gem 'guard'
  gem 'guard-minitest'
bundle
guard init minitest
vi Guardfile
# uncomment rails section
# change some lines in Guardfile
guard :minitest, spring: 'bin/rails test', failed_mode: :focus do

• to show full backtrace use BACKTRACE=blegga rails test

• to take screenshot you can call take_screenshot in tests. Automatically taking screenshot when tast fails is included in teardown by default, and you can override it https://api.rubyonrails.org/v5.2/classes/ActionDispatch/SystemTesting/TestHelpers/ScreenshotHelper.html#method-i-take_screenshot By default image_name is method_name By default display_image will print puts image_path but we can open image

  # test/application_system_test_case.rb
  require 'test_helper'
  
  class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
    driven_by :selenium, using: :chrome, screen_size: [1400, 1400]
  
    def display_image
      system "gnome-open #{image_path} &"
      system "xdg-open #{image_path} &"
      "Opening screenshot: xdg-open #{image_path}"
    end
  end
  

• test og meta tags for jekyll
• https://gist.github.com/thbar/10be2ea924b81f78d24ab800461bfee3
• if you want to run specific test (not all tests in one test file) than you need to use require 'rails/all in config/application.rb and run by line

  ./bin/rails test test/controllers/registrations_controller_test.rb:27
  

• to set cookies you can simply use

  class ApplicationControllerTest < ActionDispatch::IntegrationTest
    test '#use_time_zone' do
      user = users(:user)
      cookies['browser.timezone'] = 'UTC'
      get root_path
    end
  end
  

• Using rails native helpers instead of timecop http://edgeapi.rubyonrails.org/classes/ActiveSupport/Testing/TimeHelpers.html Use ActiveSupport::Testing::TimeHelpers#travel (usefull when you want time to pass) and travel_to travel_back (time does not move for the duration of the test).

Test background jobs

You can test job directly by calling perform.now

# test/jobs/update_person_job_test.rb
class UpdatePersonJobTest < ActiveJob::TestCase
  test 'update score' do
    person = people(:one)
    UpdatePersonJob.perform_now(person, 3)
    assert_eqal 3, person.reload.score
  end
end

https://api.rubyonrails.org/classes/ActiveJob/TestHelper.html#method-i-assert_enqueued_jobs You can use

assert_enqueued_with job: MyJob, args: [user]
perform_enqueued_jobs
assert_performed_jobs 1

ActiveJob::Base.queue_adapter = :test will change queue adapter for all following test. You can see differences between queue adapters http://api.rubyonrails.org/v5.1.4/classes/ActiveJob/QueueAdapters.html There is test helpers like assert_performed_with http://api.rubyonrails.org/classes/ActiveJob/TestHelper.html#method-i-assert_performed_with example of use is https://github.com/eliotsykes/rspec-rails-examples/blob/master/spec/jobs/headline_scraper_job_spec.rb To send email in background Rails use mailers ActionMailer::DeliveryJob so to test sending in minitest

require 'test_helper'

class ProductTest < ActionDispatch::IntegrationTest
  # if you want to actually perform jobs
  include ActiveJob::TestHelper
  test 'mail' do
    perform_enqueued_jobs only: ActionMailer::DeliveryJob do
      ...
    end
  end

  # https://api.rubyonrails.org/v5.1/classes/ActionMailer/TestHelper.html#method-i-assert_emails
  # or you can assert that it is enqueued
  assert_enqueued_jobs 1 do
  # or you can assert how it is called `_with`
  assert_enqueued_with job: ActionMailer::DeliveryJob, args: [1, 'a'] do

  include ActionMailer::TestHelper
  test 'mail' do
    assert_performed_jobs 2, only: ActionMailer::DeliveryJob do
      product.charge(account)
    end
  end

  # for email you can assert
  assert_difference 'ActionMailer::Base.deliveries.size', 1 do
    MyJob.perform_now
  end


  # to test that no jobs are enqueued
  assert_no_enqueued_jobs do
  end
end

• test unit https://test-unit.github.io and getting started page https://github.com/test-unit/test-unit/blob/master/doc/text/getting-started.md

  # my.rb
  require "test-unit"
  
  # here is my code or
  # require "my_code"
  
  class MyTest < Test::Unit::TestCase
    def test_zero
      assert true
    end
  end
  

  and run with ruby my.rb or using https://github.com/test-unit/test-unit/blob/master/doc/text/getting-started.md#43-rakefile-no-edit omit https://test-unit.github.io/test-unit/en/Test/Unit/TestCaseOmissionSupport.html#omit-instance_method

  def test_omission
    omit
    # Not reached here
  end
  

  hooks https://test-unit.github.io/test-unit/en/Test/Unit/TestCase.html