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diff --git a/guides/source/testing.md b/guides/source/testing.md index f7103adc1c..21b0b37efa 100644 --- a/guides/source/testing.md +++ b/guides/source/testing.md @@ -141,6 +141,27 @@ users(:david).id email(david.girlfriend.email, david.location_tonight) ``` +### Rake Tasks for Running your Tests + +Rails comes with a number of built-in rake tasks to help with testing. The +table below lists the commands included in the default Rakefile when a Rails +project is created. + +| Tasks | Description | +| ----------------------- | ----------- | +| `rake test` | Runs all tests in the `test` directory. You can also run `rake` and Rails will run all tests by default | +| `rake test:controllers` | Runs all the controller tests from `test/controllers` | +| `rake test:functionals` | Runs all the functional tests from `test/controllers`, `test/mailers`, and `test/functional` | +| `rake test:helpers` | Runs all the helper tests from `test/helpers` | +| `rake test:integration` | Runs all the integration tests from `test/integration` | +| `rake test:jobs` | Runs all the job tests from `test/jobs` | +| `rake test:mailers` | Runs all the mailer tests from `test/mailers` | +| `rake test:models` | Runs all the model tests from `test/models` | +| `rake test:units` | Runs all the unit tests from `test/models`, `test/helpers`, and `test/unit` | +| `rake test:db` | Runs all tests in the `test` directory and resets the db | + +We will cover each of types Rails tests listed above in this guide. + Unit Testing your Models ------------------------ @@ -388,44 +409,9 @@ This test should now pass. By now you've caught a glimpse of some of the assertions that are available. Assertions are the worker bees of testing. They are the ones that actually perform the checks to ensure that things are going as planned. -There are a bunch of different types of assertions you can use. -Here's an extract of the assertions you can use with [`Minitest`](https://github.com/seattlerb/minitest), the default testing library used by Rails. The `[msg]` parameter is an optional string message you can specify to make your test failure messages clearer. It's not required. - -| Assertion | Purpose | -| ---------------------------------------------------------------- | ------- | -| `assert( test, [msg] )` | Ensures that `test` is true.| -| `assert_not( test, [msg] )` | Ensures that `test` is false.| -| `assert_equal( expected, actual, [msg] )` | Ensures that `expected == actual` is true.| -| `assert_not_equal( expected, actual, [msg] )` | Ensures that `expected != actual` is true.| -| `assert_same( expected, actual, [msg] )` | Ensures that `expected.equal?(actual)` is true.| -| `assert_not_same( expected, actual, [msg] )` | Ensures that `expected.equal?(actual)` is false.| -| `assert_nil( obj, [msg] )` | Ensures that `obj.nil?` is true.| -| `assert_not_nil( obj, [msg] )` | Ensures that `obj.nil?` is false.| -| `assert_empty( obj, [msg] )` | Ensures that `obj` is `empty?`.| -| `assert_not_empty( obj, [msg] )` | Ensures that `obj` is not `empty?`.| -| `assert_match( regexp, string, [msg] )` | Ensures that a string matches the regular expression.| -| `assert_no_match( regexp, string, [msg] )` | Ensures that a string doesn't match the regular expression.| -| `assert_includes( collection, obj, [msg] )` | Ensures that `obj` is in `collection`.| -| `assert_not_includes( collection, obj, [msg] )` | Ensures that `obj` is not in `collection`.| -| `assert_in_delta( expecting, actual, [delta], [msg] )` | Ensures that the numbers `expected` and `actual` are within `delta` of each other.| -| `assert_not_in_delta( expecting, actual, [delta], [msg] )` | Ensures that the numbers `expected` and `actual` are not within `delta` of each other.| -| `assert_throws( symbol, [msg] ) { block }` | Ensures that the given block throws the symbol.| -| `assert_raises( exception1, exception2, ... ) { block }` | Ensures that the given block raises one of the given exceptions.| -| `assert_nothing_raised( exception1, exception2, ... ) { block }` | Ensures that the given block doesn't raise one of the given exceptions.| -| `assert_instance_of( class, obj, [msg] )` | Ensures that `obj` is an instance of `class`.| -| `assert_not_instance_of( class, obj, [msg] )` | Ensures that `obj` is not an instance of `class`.| -| `assert_kind_of( class, obj, [msg] )` | Ensures that `obj` is or descends from `class`.| -| `assert_not_kind_of( class, obj, [msg] )` | Ensures that `obj` is not an instance of `class` and is not descending from it.| -| `assert_respond_to( obj, symbol, [msg] )` | Ensures that `obj` responds to `symbol`.| -| `assert_not_respond_to( obj, symbol, [msg] )` | Ensures that `obj` does not respond to `symbol`.| -| `assert_operator( obj1, operator, [obj2], [msg] )` | Ensures that `obj1.operator(obj2)` is true.| -| `assert_not_operator( obj1, operator, [obj2], [msg] )` | Ensures that `obj1.operator(obj2)` is false.| -| `assert_predicate ( obj, predicate, [msg] )` | Ensures that `obj.predicate` is true, e.g. `assert_predicate str, :empty?`| -| `assert_not_predicate ( obj, predicate, [msg] )` | Ensures that `obj.predicate` is false, e.g. `assert_not_predicate str, :empty?`| -| `assert_send( array, [msg] )` | Ensures that executing the method listed in `array[1]` on the object in `array[0]` with the parameters of `array[2 and up]` is true. This one is weird eh?| -| `flunk( [msg] )` | Ensures failure. This is useful to explicitly mark a test that isn't finished yet.| - -The above are subset of assertions that minitest supports. For an exhaustive & more up-to-date list, please check [Minitest API documentation](http://docs.seattlerb.org/minitest/), specifically [`Minitest::Assertions`](http://docs.seattlerb.org/minitest/Minitest/Assertions.html) +There are a bunch of different types of assertions you can use that come with [`Minitest`](https://github.com/seattlerb/minitest), the default testing library used by Rails. + +For a list of all available assertions please check the [Minitest API documentation](http://docs.seattlerb.org/minitest/), specifically [`Minitest::Assertions`](http://docs.seattlerb.org/minitest/Minitest/Assertions.html) Because of the modular nature of the testing framework, it is possible to create your own assertions. In fact, that's exactly what Rails does. It includes some specialized assertions to make your life easier. @@ -447,10 +433,24 @@ Rails adds some custom assertions of its own to the `minitest` framework: You'll see the usage of some of these assertions in the next chapter. +### A Brief Note About Minitest + +All the basic assertions such as `assert_equal` defined in `Minitest::Assertions` are also available in the classes we use in our own test cases. In fact, Rails provides the following classes for you to inherit from: + +* `ActiveSupport::TestCase` +* `ActionController::TestCase` +* `ActionMailer::TestCase` +* `ActionView::TestCase` +* `ActionDispatch::IntegrationTest` + +Each of these classes include `Minitest::Assertions`, allowing us to use all of the basic assertions in our tests. + +NOTE: For more information on `Minitest`, refer to [Minitest](http://ruby-doc.org/stdlib-2.1.0/libdoc/minitest/rdoc/MiniTest.html) + Functional Tests for Your Controllers ------------------------------------- -In Rails, testing the various actions of a single controller is called writing functional tests for that controller. Controllers handle the incoming web requests to your application and eventually respond with a rendered view. +In Rails, testing the various actions of a controller is a form of writing functional tests. Remember your controllers handle the incoming web requests to your application and eventually respond with a rendered view. When writing functional tests, you're testing how your actions handle the requests and the expected result, or response in some cases an HTML view. ### What to Include in your Functional Tests @@ -524,13 +524,13 @@ If you're familiar with the HTTP protocol, you'll know that `get` is a type of r * `head` * `delete` -All of request types are methods that you can use, however, you'll probably end up using the first two more often than the others. +All of request types have equivalent methods that you can use. In a typical C.R.U.D. application you'll be using `get`, `post`, `put` and `delete` more often. -NOTE: Functional tests do not verify whether the specified request type should be accepted by the action. Request types in this context exist to make your tests more descriptive. +NOTE: Functional tests do not verify whether the specified request type is accepted by the action, we're more concerned with the result. Request tests exist for this use case to make your tests more purposeful. ### The Four Hashes of the Apocalypse -After a request has been made using one of the 6 methods (`get`, `post`, etc.) and processed, you will have 4 Hash objects ready for use: +After a request has been made and processed, you will have 4 Hash objects ready for use: * `assigns` - Any objects that are stored as instance variables in actions for use in views. * `cookies` - Any cookies that are set. @@ -553,8 +553,8 @@ assigns["something"] assigns(:something) You also have access to three instance variables in your functional tests: * `@controller` - The controller processing the request -* `@request` - The request -* `@response` - The response +* `@request` - The request object +* `@response` - The response object ### Setting Headers and CGI variables @@ -575,6 +575,10 @@ post :create # simulate the request with custom env variable ### Testing Templates and Layouts +Eventually, you may want to test whether a specific layout is rendered in the view of a response. + +#### Asserting Templates + If you want to make sure that the response rendered the correct template and layout, you can use the `assert_template` method: @@ -583,24 +587,22 @@ test "index should render correct template and layout" do get :index assert_template :index assert_template layout: "layouts/application" + + # You can also pass a regular expression. + assert_template layout: /layouts\/application/ end ``` -Note that you cannot test for template and layout at the same time, with one call to `assert_template` method. -Also, for the `layout` test, you can give a regular expression instead of a string, but using the string, makes -things clearer. On the other hand, you have to include the "layouts" directory name even if you save your layout -file in this standard layout directory. Hence, +NOTE: You cannot test for template and layout at the same time, with a single call to `assert_template`. -```ruby -assert_template layout: "application" -``` +WARNING: You must include the "layouts" directory name even if you save your layout file in this standard layout directory. Hence, `assert_template layout: "application"` will not work. -will not work. +#### Asserting Partials -If your view renders any partial, when asserting for the layout, you have to assert for the partial at the same time. +If your view renders any partial, when asserting for the layout, you can to assert for the partial at the same time. Otherwise, assertion will fail. -Hence: +Remember, we added the "_form" partial to our creating Articles view? Let's write an assertion for that in the `:new` action now: ```ruby test "new should render correct layout" do @@ -609,27 +611,201 @@ test "new should render correct layout" do end ``` -is the correct way to assert for the layout when the view renders a partial with name `_form`. Omitting the `:partial` key in your `assert_template` call will complain. +This is the correct way to assert for when the view renders a partial with a given name. As identified by the `:partial` key passed to the `assert_template` call. -### A Fuller Functional Test Example +### Testing `flash` notices -Here's another example that uses `flash`, `assert_redirected_to`, and `assert_difference`: +If you remember from earlier one of the Four Hashes of the Apocalypse was `flash`. + +We want to add a `flash` message to our blog application whenever someone +successfully creates a new Article. + +Let's start by adding this assertion to our `test_should_create_article` test: ```ruby test "should create article" do assert_difference('Article.count') do - post :create, article: {title: 'Hi', body: 'This is my first article.'} + post :create, article: {title: 'Some title'} end + assert_redirected_to article_path(assigns(:article)) assert_equal 'Article was successfully created.', flash[:notice] end ``` -### Testing Views +If we run our test now, we should see a failure: + +```bash +$ bin/rake test test/controllers/articles_controller_test.rb test_should_create_article +Run options: -n test_should_create_article --seed 32266 + +# Running: + +F + +Finished in 0.114870s, 8.7055 runs/s, 34.8220 assertions/s. + + 1) Failure: +ArticlesControllerTest#test_should_create_article [/Users/zzak/code/bench/sharedapp/test/controllers/articles_controller_test.rb:16]: +--- expected ++++ actual +@@ -1 +1 @@ +-"Article was successfully created." ++nil + +1 runs, 4 assertions, 1 failures, 0 errors, 0 skips +``` + +Let's implement the flash message now in our controller. Our `:create` action should now look like this: + +```ruby +def create + @article = Article.new(article_params) + + if @article.save + flash[:notice] = 'Article was successfully created.' + redirect_to @article + else + render 'new' + end +end +``` + +Now if we run our tests, we should see it pass: -Testing the response to your request by asserting the presence of key HTML elements and their content is a useful way to test the views of your application. The `assert_select` assertion allows you to do this by using a simple yet powerful syntax. +```bash +$ bin/rake test test/controllers/articles_controller_test.rb test_should_create_article +Run options: -n test_should_create_article --seed 18981 -NOTE: You may find references to `assert_tag` in other documentation. This has been removed in 4.2. Use `assert_select` instead. +# Running: + +. + +Finished in 0.081972s, 12.1993 runs/s, 48.7972 assertions/s. + +1 runs, 4 assertions, 0 failures, 0 errors, 0 skips +``` + +### Putting it together + +At this point our Articles controller tests the `:index` as well as `:new` and `:create` actions. What about dealing with existing data? + +Let's write a test for the `:show` action: + +```ruby +test "should show article" do + article = articles(:one) + get :show, id: article.id + assert_response :success +end +``` + +Remember from our discussion earlier on fixtures the `articles()` method will give us access to our Articles fixtures. + +How about deleting an existing Article? + +```ruby +test "should destroy article" do + article = articles(:one) + assert_difference('Article.count', -1) do + delete :destroy, id: article.id + end + + assert_redirected_to articles_path +end +``` + +We can also add a test for updating an existing Article. + +```ruby +test "should update article" do + article = articles(:one) + patch :update, id: article.id, article: {title: "updated"} + assert_redirected_to article_path(assigns(:article)) +end +``` + +Notice we're starting to see some duplication in these three tests, they both access the same Article fixture data. We can D.R.Y. this up by using the `setup` and `teardown` methods provided by `ActiveSupport::Callbacks`. + +Our test should now look something like this, disregard the other tests we're leaving them out for brevity. + +```ruby +require 'test_helper' + +class ArticlesControllerTest < ActionController::TestCase + # called before every single test + def setup + @article = articles(:one) + end + + # called after every single test + def teardown + # as we are re-initializing @article before every test + # setting it to nil here is not essential but I hope + # you understand how you can use the teardown method + @article = nil + end + + test "should show article" do + # Reuse the @article instance variable from setup + get :show, id: @article.id + assert_response :success + end + + test "should destroy article" do + assert_difference('Article.count', -1) do + delete :destroy, id: @article.id + end + + assert_redirected_to articles_path + end + + test "should update article" do + patch :update, id: @article.id, article: {title: "updated"} + assert_redirected_to article_path(assigns(:article)) + end +end +``` + +Similar to other callbacks in Rails, the `setup` and `teardown` methods can also be used by passing a block, lambda, or method name as a symbol to call. + +Testing Routes +-------------- + +Like everything else in your Rails application, it is recommended that you test your routes. Below are example tests for the routes of default `show` and `create` action of `Articles` controller above and it should look like: + +```ruby +class ArticleRoutesTest < ActionController::TestCase + test "should route to article" do + assert_routing '/articles/1', { controller: "articles", action: "show", id: "1" } + end + + test "should route to create article" do + assert_routing({ method: 'post', path: '/articles' }, { controller: "articles", action: "create" }) + end +end +``` + +I've added this file here `test/controllers/articles_routes_test.rb` and if we run the test we should see: + +```bash +$ bin/rake test test/controllers/articles_routes_test.rb + +# Running: + +.. + +Finished in 0.069381s, 28.8263 runs/s, 86.4790 assertions/s. + +2 runs, 6 assertions, 0 failures, 0 errors, 0 skips +``` + +For more information on routing assertions available in Rails, see the API documentation for [`ActionDispatch::Assertions::RoutingAssertions`](http://api.rubyonrails.org/classes/ActionDispatch/Assertions/RoutingAssertions.html). + +Testing Views +------------- + +Testing the response to your request by asserting the presence of key HTML elements and their content is a common way to test the views of your application. The `assert_select` method allows you to query HTML elements of the response by using a simple yet powerful syntax. There are two forms of `assert_select`: @@ -643,7 +819,10 @@ For example, you could verify the contents on the title element in your response assert_select 'title', "Welcome to Rails Testing Guide" ``` -You can also use nested `assert_select` blocks. In this case the inner `assert_select` runs the assertion on the complete collection of elements selected by the outer `assert_select` block: +You can also use nested `assert_select` blocks for deeper investigation. + +In the following example, the inner `assert_select` for `li.menu_item` runs +within the collection of elements selected by the outer block: ```ruby assert_select 'ul.navigation' do @@ -651,7 +830,9 @@ assert_select 'ul.navigation' do end ``` -Alternatively the collection of elements selected by the outer `assert_select` may be iterated through so that `assert_select` may be called separately for each element. Suppose for example that the response contains two ordered lists, each with four list elements then the following tests will both pass. +A collection of selected elements may be iterated through so that `assert_select` may be called separately for each element. + +For example if the response contains two ordered lists, each with four nested list elements then the following tests will both pass. ```ruby assert_select "ol" do |elements| @@ -665,7 +846,7 @@ assert_select "ol" do end ``` -The `assert_select` assertion is quite powerful. For more advanced usage, refer to its [documentation](https://github.com/rails/rails-dom-testing/blob/master/lib/rails/dom/testing/assertions/selector_assertions.rb). +This assertion is quite powerful. For more advanced usage, refer to its [documentation](http://www.rubydoc.info/github/rails/rails-dom-testing). #### Additional View-Based Assertions @@ -685,12 +866,45 @@ assert_select_email do end ``` +Testing helpers +--------------- + +In order to test helpers, all you need to do is check that the output of the +helper method matches what you'd expect. Tests related to the helpers are +located under the `test/helpers` directory. + +A helper test looks like so: + +```ruby +require 'test_helper' + +class UserHelperTest < ActionView::TestCase +end +``` + +A helper is just a simple module where you can define methods which are +available into your views. To test the output of the helper's methods, you just +have to use a mixin like this: + +```ruby +class UserHelperTest < ActionView::TestCase + include UserHelper + + test "should return the user name" do + # ... + end +end +``` + +Moreover, since the test class extends from `ActionView::TestCase`, you have +access to Rails' helper methods such as `link_to` or `pluralize`. + Integration Testing ------------------- -Integration tests are used to test the interaction among any number of controllers. They are generally used to test important work flows within your application. +Integration tests are used to test how various parts of your application interact. They are generally used to test important work flows within your application. -Unlike Unit and Functional tests, integration tests have to be explicitly created under the 'test/integration' directory within your application. Rails provides a generator to create an integration test skeleton for you. +For creating Rails integration tests, we use the 'test/integration' directory for your application. Rails provides a generator to create an integration test skeleton for you. ```bash $ bin/rails generate integration_test user_flows @@ -710,233 +924,92 @@ class UserFlowsTest < ActionDispatch::IntegrationTest end ``` -Integration tests inherit from `ActionDispatch::IntegrationTest`. This makes available some additional helpers to use in your integration tests. Also you need to explicitly include the fixtures to be made available to the test. +Inheriting from `ActionDispatch::IntegrationTest` comes with some advantages. This makes available some additional helpers to use in your integration tests. ### Helpers Available for Integration Tests -In addition to the standard testing helpers, there are some additional helpers available to integration tests: +In addition to the standard testing helpers, inheriting `ActionDispatch::IntegrationTest` comes with some additional helpers available when writing integration tests. Let's briefly introduce you to the three categories of helpers you get to choose from. -| Helper | Purpose | -| ------------------------------------------------------------------ | ------- | -| `https?` | Returns `true` if the session is mimicking a secure HTTPS request.| -| `https!` | Allows you to mimic a secure HTTPS request.| -| `host!` | Allows you to set the host name to use in the next request.| -| `redirect?` | Returns `true` if the last request was a redirect.| -| `follow_redirect!` | Follows a single redirect response.| -| `request_via_redirect(http_method, path, [parameters], [headers])` | Allows you to make an HTTP request and follow any subsequent redirects.| -| `post_via_redirect(path, [parameters], [headers])` | Allows you to make an HTTP POST request and follow any subsequent redirects.| -| `get_via_redirect(path, [parameters], [headers])` | Allows you to make an HTTP GET request and follow any subsequent redirects.| -| `patch_via_redirect(path, [parameters], [headers])` | Allows you to make an HTTP PATCH request and follow any subsequent redirects.| -| `put_via_redirect(path, [parameters], [headers])` | Allows you to make an HTTP PUT request and follow any subsequent redirects.| -| `delete_via_redirect(path, [parameters], [headers])` | Allows you to make an HTTP DELETE request and follow any subsequent redirects.| -| `open_session` | Opens a new session instance.| +For dealing with the integration test runner, see [`ActionDispatch::Integration::Runner`](http://api.rubyonrails.org/classes/ActionDispatch/Integration/Runner.html). -### Integration Testing Examples +When performing requests, you will have [`ActionDispatch::Integration::RequestHelpers`](http://api.rubyonrails.org/classes/ActionDispatch/Integration/RequestHelpers.html) available for your use. -A simple integration test that exercises multiple controllers: +If you'd like to modify the session, or state of your integration test you should look for [`ActionDispatch::Integration::Session`](http://api.rubyonrails.org/classes/ActionDispatch/Integration/Session.html) to help. -```ruby -require 'test_helper' +### Implementing an integration test -class UserFlowsTest < ActionDispatch::IntegrationTest - test "login and browse site" do - # login via https - https! - get "/login" - assert_response :success +Let's add an integration test to our blog application. We'll start with a basic workflow of creating a new blog article, to verify that everything is working properly. - post_via_redirect "/login", username: users(:david).username, password: users(:david).password - assert_equal '/welcome', path - assert_equal 'Welcome david!', flash[:notice] +We'll start by generating our integration test skeleton: - https!(false) - get "/articles/all" - assert_response :success - assert assigns(:articles) - end -end +```bash +$ bin/rails generate integration_test blog_flow ``` -As you can see the integration test involves multiple controllers and exercises the entire stack from database to dispatcher. In addition you can have multiple session instances open simultaneously in a test and extend those instances with assertion methods to create a very powerful testing DSL (domain-specific language) just for your application. +It should have created a test file placeholder for us, with the output of the previous command you should see: + +```bash + invoke test_unit + create test/integration/blog_flow_test.rb +``` -Here's an example of multiple sessions and custom DSL in an integration test +Now let's open that file and write our first assertion: ```ruby require 'test_helper' -class UserFlowsTest < ActionDispatch::IntegrationTest - test "login and browse site" do - # User david logs in - david = login(:david) - # User guest logs in - guest = login(:guest) - - # Both are now available in different sessions - assert_equal 'Welcome david!', david.flash[:notice] - assert_equal 'Welcome guest!', guest.flash[:notice] - - # User david can browse site - david.browses_site - # User guest can browse site as well - guest.browses_site - - # Continue with other assertions +class BlogFlowTest < ActionDispatch::IntegrationTest + test "can see the welcome page" do + get "/" + assert_select "h1", "Welcome#index" end - - private - - module CustomDsl - def browses_site - get "/products/all" - assert_response :success - assert assigns(:products) - end - end - - def login(user) - open_session do |sess| - sess.extend(CustomDsl) - u = users(user) - sess.https! - sess.post "/login", username: u.username, password: u.password - assert_equal '/welcome', sess.path - sess.https!(false) - end - end end ``` -Rake Tasks for Running your Tests ---------------------------------- - -Rails comes with a number of built-in rake tasks to help with testing. The -table below lists the commands included in the default Rakefile when a Rails -project is created. - -| Tasks | Description | -| ----------------------- | ----------- | -| `rake test` | Runs all tests in the `test` directory. You can also run `rake` and Rails will run all tests by default | -| `rake test:controllers` | Runs all the controller tests from `test/controllers` | -| `rake test:functionals` | Runs all the functional tests from `test/controllers`, `test/mailers`, and `test/functional` | -| `rake test:helpers` | Runs all the helper tests from `test/helpers` | -| `rake test:integration` | Runs all the integration tests from `test/integration` | -| `rake test:jobs` | Runs all the job tests from `test/jobs` | -| `rake test:mailers` | Runs all the mailer tests from `test/mailers` | -| `rake test:models` | Runs all the model tests from `test/models` | -| `rake test:units` | Runs all the unit tests from `test/models`, `test/helpers`, and `test/unit` | -| `rake test:db` | Runs all tests in the `test` directory and resets the db | - +If you remember from earlier in the "Testing Views" section we covered `assert_select` to query the resulting HTML of a request. -A Brief Note About Minitest ------------------------------ +When visit our root path, we should see `welcome/index.html.erb` rendered for the view. So this assertion should pass. -Ruby ships with a vast Standard Library for all common use-cases including testing. Since version 1.9, Ruby provides `Minitest`, a framework for testing. All the basic assertions such as `assert_equal` discussed above are actually defined in `Minitest::Assertions`. The classes `ActiveSupport::TestCase`, `ActionController::TestCase`, `ActionMailer::TestCase`, `ActionView::TestCase` and `ActionDispatch::IntegrationTest` - which we have been inheriting in our test classes - include `Minitest::Assertions`, allowing us to use all of the basic assertions in our tests. +#### Creating articles integration -NOTE: For more information on `Minitest`, refer to [Minitest](http://ruby-doc.org/stdlib-2.1.0/libdoc/minitest/rdoc/MiniTest.html) - -Setup and Teardown ------------------- - -If you would like to run a block of code before the start of each test and another block of code after the end of each test you have two special callbacks for your rescue. Let's take note of this by looking at an example for our functional test in `Articles` controller: +How about testing our ability to create a new article in our blog and see the resulting article. ```ruby -require 'test_helper' - -class ArticlesControllerTest < ActionController::TestCase - - # called before every single test - def setup - @article = articles(:one) - end - - # called after every single test - def teardown - # as we are re-initializing @article before every test - # setting it to nil here is not essential but I hope - # you understand how you can use the teardown method - @article = nil - end - - test "should show article" do - get :show, id: @article.id - assert_response :success - end - - test "should destroy article" do - assert_difference('Article.count', -1) do - delete :destroy, id: @article.id - end - - assert_redirected_to articles_path - end - +test "can create an article" do + get "/articles/new" + assert_response :success + assert_template "articles/new", partial: "articles/_form" + + post "/articles", article: {title: "can create", body: "article successfully."} + assert_response :redirect + follow_redirect! + assert_response :success + assert_template "articles/show" + assert_select "p", "Title:\n can create" end ``` -Above, the `setup` method is called before each test and so `@article` is available for each of the tests. Rails implements `setup` and `teardown` as `ActiveSupport::Callbacks`. Which essentially means you need not only use `setup` and `teardown` as methods in your tests. You could specify them by using: +Let's break this test down so we can understand it. -* a block -* a method (like in the earlier example) -* a method name as a symbol -* a lambda +We start by calling the `:new` action on our Articles controller. This response should be successful, and we can verify the correct template is rendered including the form partial. -Let's see the earlier example by specifying `setup` callback by specifying a method name as a symbol: +After this we make a post request to the `:create` action of our Articles controller: ```ruby -require 'test_helper' - -class ArticlesControllerTest < ActionController::TestCase - - # called before every single test - setup :initialize_article - - # called after every single test - def teardown - @article = nil - end - - test "should show article" do - get :show, id: @article.id - assert_response :success - end - - test "should update article" do - patch :update, id: @article.id, article: {} - assert_redirected_to article_path(assigns(:article)) - end - - test "should destroy article" do - assert_difference('Article.count', -1) do - delete :destroy, id: @article.id - end - - assert_redirected_to articles_path - end - - private - - def initialize_article - @article = articles(:one) - end -end +post "/articles", article: {title: "can create", body: "article successfully."} +assert_response :redirect +follow_redirect! ``` -Testing Routes --------------- +The two lines following the request are to handle the redirect we setup when creating a new article. -Like everything else in your Rails application, it is recommended that you test your routes. Below are example tests for the routes of default `show` and `create` action of `Articles` controller above and it should look like: +NOTE: Don't forget to call `follow_redirect!` if you plan to make subsequent requests after a redirect is made. -```ruby -class ArticleRoutesTest < ActionController::TestCase - test "should route to article" do - assert_routing '/articles/1', { controller: "articles", action: "show", id: "1" } - end +Finally we can assert that our response was successful, template was rendered, and our new article is readable on the page. - test "should route to create article" do - assert_routing({ method: 'post', path: '/articles' }, { controller: "articles", action: "create" }) - end -end -``` +#### Taking it further + +We were able to successfully test a very small workflow for visiting our blog and creating a new article. If we wanted to take this further we could add tests for commenting, removing articles, or editting comments. Integration tests are a great place to experiment with all kinds of use-cases for our applications. Testing Your Mailers -------------------- @@ -1038,39 +1111,6 @@ class UserControllerTest < ActionController::TestCase end ``` -Testing helpers ---------------- - -In order to test helpers, all you need to do is check that the output of the -helper method matches what you'd expect. Tests related to the helpers are -located under the `test/helpers` directory. - -A helper test looks like so: - -```ruby -require 'test_helper' - -class UserHelperTest < ActionView::TestCase -end -``` - -A helper is just a simple module where you can define methods which are -available into your views. To test the output of the helper's methods, you just -have to use a mixin like this: - -```ruby -class UserHelperTest < ActionView::TestCase - include UserHelper - - test "should return the user name" do - # ... - end -end -``` - -Moreover, since the test class extends from `ActionView::TestCase`, you have -access to Rails' helper methods such as `link_to` or `pluralize`. - Testing Jobs ------------ @@ -1104,17 +1144,7 @@ no jobs have already been executed in the scope of each test. ### Custom Assertions And Testing Jobs Inside Other Components -Active Job ships with a bunch of custom assertions that can be used to lessen -the verbosity of tests: - -| Assertion | Purpose | -| -------------------------------------- | ------- | -| `assert_enqueued_jobs(number)` | Asserts that the number of enqueued jobs matches the given number. | -| `assert_performed_jobs(number)` | Asserts that the number of performed jobs matches the given number. | -| `assert_no_enqueued_jobs { ... }` | Asserts that no jobs have been enqueued. | -| `assert_no_performed_jobs { ... }` | Asserts that no jobs have been performed. | -| `assert_enqueued_with([args]) { ... }` | Asserts that the job passed in the block has been enqueued with the given arguments. | -| `assert_performed_with([args]) { ... }`| Asserts that the job passed in the block has been performed with the given arguments. | +Active Job ships with a bunch of custom assertions that can be used to lessen the verbosity of tests. For a full list of available assertions, see the API documentation for [`ActiveJob::TestHelper`](http://api.rubyonrails.org/classes/ActiveJob/TestHelper.html). It's a good practice to ensure that your jobs correctly get enqueued or performed wherever you invoke them (e.g. inside your controllers). This is precisely where |