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diff --git a/guides/source/testing.md b/guides/source/testing.md index a9bce04522..d54f431d54 100644 --- a/guides/source/testing.md +++ b/guides/source/testing.md @@ -1,8 +1,7 @@ A Guide to Testing Rails Applications ===================================== -This guide covers built-in mechanisms offered by Rails to test your -application. +This guide covers built-in mechanisms in Rails for testing your application. After reading this guide, you will know: @@ -38,11 +37,11 @@ Rails creates a `test` folder for you as soon as you create a Rails project usin ```bash $ ls -F test - -fixtures/ functional/ integration/ performance/ test_helper.rb unit/ +controllers/ helpers/ mailers/ test_helper.rb +fixtures/ integration/ models/ ``` -The `unit` directory is meant to hold tests for your models, the `functional` directory is meant to hold tests for your controllers, the `integration` directory is meant to hold tests that involve any number of controllers interacting, and the `performance` directory is meant for performance tests. +The `models` directory is meant to hold tests for your models, the `controllers` directory is meant to hold tests for your controllers and the `integration` directory is meant to hold tests that involve any number of controllers interacting. Fixtures are a way of organizing test data; they reside in the `fixtures` folder. @@ -50,7 +49,9 @@ The `test_helper.rb` file holds the default configuration for your tests. ### The Low-Down on Fixtures -For good tests, you'll need to give some thought to setting up test data. In Rails, you can handle this by defining and customizing fixtures. +For good tests, you'll need to give some thought to setting up test data. +In Rails, you can handle this by defining and customizing fixtures. +You can find comprehensive documentation in the [Fixtures API documentation](http://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html). #### What Are Fixtures? @@ -65,19 +66,41 @@ YAML-formatted fixtures are a very human-friendly way to describe your sample da Here's a sample YAML fixture file: ```yaml -# lo & behold! I am a YAML comment! +# lo & behold! I am a YAML comment! david: - name: David Heinemeier Hansson - birthday: 1979-10-15 - profession: Systems development + name: David Heinemeier Hansson + birthday: 1979-10-15 + profession: Systems development steve: - name: Steve Ross Kellock - birthday: 1974-09-27 - profession: guy with keyboard + name: Steve Ross Kellock + birthday: 1974-09-27 + profession: guy with keyboard ``` -Each fixture is given a name followed by an indented list of colon-separated key/value pairs. Records are typically separated by a blank space. You can place comments in a fixture file by using the # character in the first column. +Each fixture is given a name followed by an indented list of colon-separated key/value pairs. Records are typically separated by a blank space. You can place comments in a fixture file by using the # character in the first column. Keys which resemble YAML keywords such as 'yes' and 'no' are quoted so that the YAML Parser correctly interprets them. + +If you are working with [associations](/association_basics.html), you can simply +define a reference node between two different fixtures. Here's an example with +a `belongs_to`/`has_many` association: + +```yaml +# In fixtures/categories.yml +about: + name: About + +# In fixtures/articles.yml +one: + title: Welcome to Rails! + body: Hello world! + category: about +``` + +Note: For associations to reference one another by name, you cannot specify the `id:` + attribute on the fixtures. Rails will auto assign a primary key to be consistent between + runs. If you manually specify an `id:` attribute, this behavior will not work. For more + information on this association behavior please read the + [Fixtures API documentation](http://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html). #### ERB'in It Up @@ -86,14 +109,14 @@ ERB allows you to embed Ruby code within templates. The YAML fixture format is p ```erb <% 1000.times do |n| %> user_<%= n %>: - username: <%= "user%03d" % n %> - email: <%= "user%03d@example.com" % n %> + username: <%= "user#{n}" %> + email: <%= "user#{n}@example.com" %> <% end %> ``` #### Fixtures in Action -Rails by default automatically loads all fixtures from the `test/fixtures` folder for your unit and functional test. Loading involves three steps: +Rails by default automatically loads all fixtures from the `test/fixtures` folder for your models and controllers test. Loading involves three steps: * Remove any existing data from the table corresponding to the fixture * Load the fixture data into the table @@ -117,33 +140,32 @@ email(david.girlfriend.email, david.location_tonight) Unit Testing your Models ------------------------ -In Rails, unit tests are what you write to test your models. +In Rails, models tests are what you write to test your models. -For this guide we will be using Rails _scaffolding_. It will create the model, a migration, controller and views for the new resource in a single operation. It will also create a full test suite following Rails best practices. I will be using examples from this generated code and will be supplementing it with additional examples where necessary. +For this guide we will be using Rails _scaffolding_. It will create the model, a migration, controller and views for the new resource in a single operation. It will also create a full test suite following Rails best practices. We will be using examples from this generated code and will be supplementing it with additional examples where necessary. -NOTE: For more information on Rails <i>scaffolding</i>, refer to [Getting Started with Rails](getting_started.html) +NOTE: For more information on Rails _scaffolding_, refer to [Getting Started with Rails](getting_started.html) When you use `rails generate scaffold`, for a resource among other things it creates a test stub in the `test/models` folder: ```bash -$ rails generate scaffold post title:string body:text +$ bin/rails generate scaffold article title:string body:text ... -create app/models/post.rb -create test/models/post_test.rb -create test/fixtures/posts.yml +create app/models/article.rb +create test/models/article_test.rb +create test/fixtures/articles.yml ... ``` -The default test stub in `test/models/post_test.rb` looks like this: +The default test stub in `test/models/article_test.rb` looks like this: ```ruby require 'test_helper' -class PostTest < ActiveSupport::TestCase - # Replace this with your real tests. - test "the truth" do - assert true - end +class ArticleTest < ActiveSupport::TestCase + # test "the truth" do + # assert true + # end end ``` @@ -156,14 +178,15 @@ require 'test_helper' As you know by now, `test_helper.rb` specifies the default configuration to run our tests. This is included with all the tests, so any methods added to this file are available to all your tests. ```ruby -class PostTest < ActiveSupport::TestCase +class ArticleTest < ActiveSupport::TestCase ``` -The `PostTest` class defines a _test case_ because it inherits from `ActiveSupport::TestCase`. `PostTest` thus has all the methods available from `ActiveSupport::TestCase`. You'll see those methods a little later in this guide. +The `ArticleTest` class defines a _test case_ because it inherits from `ActiveSupport::TestCase`. `ArticleTest` thus has all the methods available from `ActiveSupport::TestCase`. You'll see those methods a little later in this guide. -Any method defined within a `Test::Unit` test case that begins with `test` (case sensitive) is simply called a test. So, `test_password`, `test_valid_password` and `testValidPassword` all are legal test names and are run automatically when the test case is run. +Any method defined within a class inherited from `Minitest::Test` +(which is the superclass of `ActiveSupport::TestCase`) that begins with `test_` (case sensitive) is simply called a test. So, `test_password` and `test_valid_password` are legal test names and are run automatically when the test case is run. -Rails adds a `test` method that takes a test name and a block. It generates a normal `Test::Unit` test with method names prefixed with `test_`. So, +Rails adds a `test` method that takes a test name and a block. It generates a normal `Minitest::Unit` test with method names prefixed with `test_`. So, ```ruby test "the truth" do @@ -196,95 +219,68 @@ This line of code is called an _assertion_. An assertion is a line of code that Every test contains one or more assertions. Only when all the assertions are successful will the test pass. -### Preparing your Application for Testing - -Before you can run your tests, you need to ensure that the test database structure is current. For this you can use the following rake commands: - -```bash -$ rake db:migrate -... -$ rake db:test:load -``` - -The `rake db:migrate` above runs any pending migrations on the _development_ environment and updates `db/schema.rb`. The `rake db:test:load` recreates the test database from the current `db/schema.rb`. On subsequent attempts, it is a good idea to first run `db:test:prepare`, as it first checks for pending migrations and warns you appropriately. +### Maintaining the test database schema -NOTE: `db:test:prepare` will fail with an error if `db/schema.rb` doesn't exist. - -#### Rake Tasks for Preparing your Application for Testing - -| Tasks | Description | -| ------------------------------ | ------------------------------------------------------------------------- | -| `rake db:test:clone` | Recreate the test database from the current environment's database schema | -| `rake db:test:clone_structure` | Recreate the test database from the development structure | -| `rake db:test:load` | Recreate the test database from the current `schema.rb` | -| `rake db:test:prepare` | Check for pending migrations and load the test schema | -| `rake db:test:purge` | Empty the test database. | - -TIP: You can see all these rake tasks and their descriptions by running `rake --tasks --describe` +In order to run your tests, your test database will need to have the current structure. The test helper checks whether your test database has any pending migrations. If so, it will try to load your `db/schema.rb` or `db/structure.sql` into the test database. If migrations are still pending, an error will be raised. ### Running Tests -Running a test is as simple as invoking the file containing the test cases through Ruby: +Running a test is as simple as invoking the file containing the test cases through `rake test` command. ```bash -$ ruby -Itest test/models/post_test.rb - -Loaded suite models/post_test -Started +$ bin/rake test test/models/article_test.rb . -Finished in 0.023513 seconds. -1 tests, 1 assertions, 0 failures, 0 errors -``` +Finished tests in 0.009262s, 107.9680 tests/s, 107.9680 assertions/s. -This will run all the test methods from the test case. Note that `test_helper.rb` is in the `test` directory, hence this directory needs to be added to the load path using the `-I` switch. +1 tests, 1 assertions, 0 failures, 0 errors, 0 skips +``` -You can also run a particular test method from the test case by using the `-n` switch with the `test method name`. +You can also run a particular test method from the test case by running the test and providing the `test method name`. ```bash -$ ruby -Itest test/models/post_test.rb -n test_the_truth - -Loaded suite models/post_test -Started +$ bin/rake test test/models/article_test.rb test_the_truth . -Finished in 0.023513 seconds. -1 tests, 1 assertions, 0 failures, 0 errors +Finished tests in 0.009064s, 110.3266 tests/s, 110.3266 assertions/s. + +1 tests, 1 assertions, 0 failures, 0 errors, 0 skips ``` +This will run all test methods from the test case. Note that `test_helper.rb` is in the `test` directory, hence this directory needs to be added to the load path using the `-I` switch. + The `.` (dot) above indicates a passing test. When a test fails you see an `F`; when a test throws an error you see an `E` in its place. The last line of the output is the summary. -To see how a test failure is reported, you can add a failing test to the `post_test.rb` test case. +To see how a test failure is reported, you can add a failing test to the `article_test.rb` test case. ```ruby -test "should not save post without title" do - post = Post.new - assert !post.save +test "should not save article without title" do + article = Article.new + assert_not article.save end ``` Let us run this newly added test. ```bash -$ ruby unit/post_test.rb -n test_should_not_save_post_without_title -Loaded suite -e -Started +$ bin/rake test test/models/article_test.rb test_should_not_save_article_without_title F -Finished in 0.102072 seconds. + +Finished tests in 0.044632s, 22.4054 tests/s, 22.4054 assertions/s. 1) Failure: -test_should_not_save_post_without_title(PostTest) [/test/models/post_test.rb:6]: -<false> is not true. +test_should_not_save_article_without_title(ArticleTest) [test/models/article_test.rb:6]: +Failed assertion, no message given. -1 tests, 1 assertions, 1 failures, 0 errors +1 tests, 1 assertions, 1 failures, 0 errors, 0 skips ``` In the output, `F` denotes a failure. You can see the corresponding trace shown under `1)` along with the name of the failing test. The next few lines contain the stack trace followed by a message which mentions the actual value and the expected value by the assertion. The default assertion messages provide just enough information to help pinpoint the error. To make the assertion failure message more readable, every assertion provides an optional message parameter, as shown here: ```ruby -test "should not save post without title" do - post = Post.new - assert !post.save, "Saved the post without a title" +test "should not save article without title" do + article = Article.new + assert_not article.save, "Saved the article without a title" end ``` @@ -292,15 +288,14 @@ Running this test shows the friendlier assertion message: ```bash 1) Failure: -test_should_not_save_post_without_title(PostTest) [/test/models/post_test.rb:6]: -Saved the post without a title. -<false> is not true. +test_should_not_save_article_without_title(ArticleTest) [test/models/article_test.rb:6]: +Saved the article without a title ``` Now to get this test to pass we can add a model level validation for the _title_ field. ```ruby -class Post < ActiveRecord::Base +class Article < ActiveRecord::Base validates :title, presence: true end ``` @@ -308,13 +303,12 @@ end Now the test should pass. Let us verify by running the test again: ```bash -$ ruby unit/post_test.rb -n test_should_not_save_post_without_title -Loaded suite unit/post_test -Started +$ bin/rake test test/models/article_test.rb test_should_not_save_article_without_title . -Finished in 0.193608 seconds. -1 tests, 1 assertions, 0 failures, 0 errors +Finished tests in 0.047721s, 20.9551 tests/s, 20.9551 assertions/s. + +1 tests, 1 assertions, 0 failures, 0 errors, 0 skips ``` Now, if you noticed, we first wrote a test which fails for a desired functionality, then we wrote some code which adds the functionality and finally we ensured that our test passes. This approach to software development is referred to as _Test-Driven Development_ (TDD). @@ -334,63 +328,88 @@ end Now you can see even more output in the console from running the tests: ```bash -$ ruby unit/post_test.rb -n test_should_report_error -Loaded suite -e -Started +$ bin/rake test test/models/article_test.rb test_should_report_error E -Finished in 0.082603 seconds. + +Finished tests in 0.030974s, 32.2851 tests/s, 0.0000 assertions/s. 1) Error: -test_should_report_error(PostTest): -NameError: undefined local variable or method `some_undefined_variable' for #<PostTest:0x249d354> - /test/models/post_test.rb:6:in `test_should_report_error' +test_should_report_error(ArticleTest): +NameError: undefined local variable or method `some_undefined_variable' for #<ArticleTest:0x007fe32e24afe0> + test/models/article_test.rb:10:in `block in <class:ArticleTest>' -1 tests, 0 assertions, 0 failures, 1 errors +1 tests, 0 assertions, 0 failures, 1 errors, 0 skips ``` Notice the 'E' in the output. It denotes a test with error. NOTE: The execution of each test method stops as soon as any error or an assertion failure is encountered, and the test suite continues with the next method. All test methods are executed in alphabetical order. +When a test fails you are presented with the corresponding backtrace. By default +Rails filters that backtrace and will only print lines relevant to your +application. This eliminates the framework noise and helps to focus on your +code. However there are situations when you want to see the full +backtrace. simply set the `BACKTRACE` environment variable to enable this +behavior: + +```bash +$ BACKTRACE=1 bin/rake test test/models/article_test.rb +``` + ### What to Include in Your Unit Tests Ideally, you would like to include a test for everything which could possibly break. It's a good practice to have at least one test for each of your validations and at least one test for every method in your model. -### Assertions Available +### Available Assertions 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 the complete list of assertions that ship with `test/unit`, 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. +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( boolean, [msg] )` | Ensures that the object/expression is true.| +| `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 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 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_in_delta( expecting, actual, delta, [msg] )` | Ensures that the numbers `expecting` and `actual` are within `delta` of each other.| +| `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_raise( exception1, exception2, ... ) { block }` | Ensures that the given block raises one of the given exceptions.| +| `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 of the `class` type.| +| `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_respond_to( obj, symbol, [msg] )` | Ensures that `obj` has a method called `symbol`.| -| `assert_operator( obj1, operator, obj2, [msg] )` | Ensures that `obj1.operator(obj2)` is true.| +| `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) + 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. NOTE: Creating your own assertions is an advanced topic that we won't cover in this tutorial. ### Rails Specific Assertions -Rails adds some custom assertions of its own to the `test/unit` framework: +Rails adds some custom assertions of its own to the `minitest` framework: | Assertion | Purpose | | --------------------------------------------------------------------------------- | ------- | @@ -398,8 +417,8 @@ Rails adds some custom assertions of its own to the `test/unit` framework: | `assert_no_difference(expressions, message = nil, &block)` | Asserts that the numeric result of evaluating an expression is not changed before and after invoking the passed in block.| | `assert_recognizes(expected_options, path, extras={}, message=nil)` | Asserts that the routing of the given path was handled correctly and that the parsed options (given in the expected_options hash) match path. Basically, it asserts that Rails recognizes the route given by expected_options.| | `assert_generates(expected_path, options, defaults={}, extras = {}, message=nil)` | Asserts that the provided options can be used to generate the provided path. This is the inverse of assert_recognizes. The extras parameter is used to tell the request the names and values of additional request parameters that would be in a query string. The message parameter allows you to specify a custom error message for assertion failures.| -| `assert_response(type, message = nil)` | Asserts that the response comes with a specific status code. You can specify `:success` to indicate 200-299, `:redirect` to indicate 300-399, `:missing` to indicate 404, or `:error` to match the 500-599 range| -| `assert_redirected_to(options = {}, message=nil)` | Assert that the redirection options passed in match those of the redirect called in the latest action. This match can be partial, such that `assert_redirected_to(controller: "weblog")` will also match the redirection of `redirect_to(controller: "weblog", action: "show")` and so on.| +| `assert_response(type, message = nil)` | Asserts that the response comes with a specific status code. You can specify `:success` to indicate 200-299, `:redirect` to indicate 300-399, `:missing` to indicate 404, or `:error` to match the 500-599 range. You can also pass an explicit status number or its symbolic equivalent. For more information, see [full list of status codes](http://rubydoc.info/github/rack/rack/master/Rack/Utils#HTTP_STATUS_CODES-constant) and how their [mapping](http://rubydoc.info/github/rack/rack/master/Rack/Utils#SYMBOL_TO_STATUS_CODE-constant) works.| +| `assert_redirected_to(options = {}, message=nil)` | Assert that the redirection options passed in match those of the redirect called in the latest action. This match can be partial, such that `assert_redirected_to(controller: "weblog")` will also match the redirection of `redirect_to(controller: "weblog", action: "show")` and so on. You can also pass named routes such as `assert_redirected_to root_path` and Active Record objects such as `assert_redirected_to @article`.| | `assert_template(expected = nil, message=nil)` | Asserts that the request was rendered with the appropriate template file.| You'll see the usage of some of these assertions in the next chapter. @@ -419,24 +438,26 @@ You should test for things such as: * was the correct object stored in the response template? * was the appropriate message displayed to the user in the view? -Now that we have used Rails scaffold generator for our `Post` resource, it has already created the controller code and tests. You can take look at the file `posts_controller_test.rb` in the `test/controllers` directory. +Now that we have used Rails scaffold generator for our `Article` resource, it has already created the controller code and tests. You can take look at the file `articles_controller_test.rb` in the `test/controllers` directory. -Let me take you through one such test, `test_should_get_index` from the file `posts_controller_test.rb`. +Let me take you through one such test, `test_should_get_index` from the file `articles_controller_test.rb`. ```ruby -test "should get index" do - get :index - assert_response :success - assert_not_nil assigns(:posts) +class ArticlesControllerTest < ActionController::TestCase + test "should get index" do + get :index + assert_response :success + assert_not_nil assigns(:articles) + end end ``` -In the `test_should_get_index` test, Rails simulates a request on the action called `index`, making sure the request was successful and also ensuring that it assigns a valid `posts` instance variable. +In the `test_should_get_index` test, Rails simulates a request on the action called `index`, making sure the request was successful and also ensuring that it assigns a valid `articles` instance variable. The `get` method kicks off the web request and populates the results into the response. It accepts 4 arguments: * The action of the controller you are requesting. This can be in the form of a string or a symbol. -* An optional hash of request parameters to pass into the action (eg. query string parameters or post variables). +* An optional hash of request parameters to pass into the action (eg. query string parameters or article variables). * An optional hash of session variables to pass along with the request. * An optional hash of flash values. @@ -452,17 +473,17 @@ Another example: Calling the `:view` action, passing an `id` of 12 as the `param get(:view, {'id' => '12'}, nil, {'message' => 'booya!'}) ``` -NOTE: If you try running `test_should_create_post` test from `posts_controller_test.rb` it will fail on account of the newly added model level validation and rightly so. +NOTE: If you try running `test_should_create_article` test from `articles_controller_test.rb` it will fail on account of the newly added model level validation and rightly so. -Let us modify `test_should_create_post` test in `posts_controller_test.rb` so that all our test pass: +Let us modify `test_should_create_article` test in `articles_controller_test.rb` so that all our test pass: ```ruby -test "should create post" do - assert_difference('Post.count') do - post :create, post: {title: 'Some title'} +test "should create article" do + assert_difference('Article.count') do + post :create, article: {title: 'Some title'} end - assert_redirected_to post_path(assigns(:post)) + assert_redirected_to article_path(assigns(:article)) end ``` @@ -485,7 +506,7 @@ NOTE: Functional tests do not verify whether the specified request type should b ### The Four Hashes of the Apocalypse -After a request has been made by using one of the 5 methods (`get`, `post`, etc.) and processed, you will have 4 Hash objects ready for use: +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: * `assigns` - Any objects that are stored as instance variables in actions for use in views. * `cookies` - Any cookies that are set. @@ -511,6 +532,23 @@ You also have access to three instance variables in your functional tests: * `@request` - The request * `@response` - The response +### Setting Headers and CGI variables + +[HTTP headers](http://tools.ietf.org/search/rfc2616#section-5.3) +and +[CGI variables](http://tools.ietf.org/search/rfc3875#section-4.1) +can be set directly on the `@request` instance variable: + +```ruby +# setting a HTTP Header +@request.headers["Accept"] = "text/plain, text/html" +get :index # simulate the request with custom header + +# setting a CGI variable +@request.headers["HTTP_REFERER"] = "http://example.com/home" +post :create # simulate the request with custom env variable +``` + ### Testing Templates and Layouts If you want to make sure that the response rendered the correct template and layout, you can use the `assert_template` @@ -554,12 +592,12 @@ is the correct way to assert for the layout when the view renders a partial with Here's another example that uses `flash`, `assert_redirected_to`, and `assert_difference`: ```ruby -test "should create post" do - assert_difference('Post.count') do - post :create, post: {title: 'Hi', body: 'This is my first post.'} +test "should create article" do + assert_difference('Article.count') do + post :create, article: {title: 'Hi', body: 'This is my first article.'} end - assert_redirected_to post_path(assigns(:post)) - assert_equal 'Post was successfully created.', flash[:notice] + assert_redirected_to article_path(assigns(:article)) + assert_equal 'Article was successfully created.', flash[:notice] end ``` @@ -567,13 +605,13 @@ end 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. -NOTE: You may find references to `assert_tag` in other documentation, but this is now deprecated in favor of `assert_select`. +NOTE: You may find references to `assert_tag` in other documentation. This has been removed in 4.2. Use `assert_select` instead. There are two forms of `assert_select`: -`assert_select(selector, [equality], [message])` ensures that the equality condition is met on the selected elements through the selector. The selector may be a CSS selector expression (String), an expression with substitution values, or an `HTML::Selector` object. +`assert_select(selector, [equality], [message])` ensures that the equality condition is met on the selected elements through the selector. The selector may be a CSS selector expression (String) or an expression with substitution values. -`assert_select(element, selector, [equality], [message])` ensures that the equality condition is met on all the selected elements through the selector starting from the _element_ (instance of `HTML::Node`) and its descendants. +`assert_select(element, selector, [equality], [message])` ensures that the equality condition is met on all the selected elements through the selector starting from the _element_ (instance of `Nokogiri::XML::Node` or `Nokogiri::XML::NodeSet`) and its descendants. For example, you could verify the contents on the title element in your response with: @@ -603,17 +641,17 @@ assert_select "ol" do end ``` -The `assert_select` assertion is quite powerful. For more advanced usage, refer to its [documentation](http://api.rubyonrails.org/classes/ActionDispatch/Assertions/SelectorAssertions.html). +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). #### Additional View-Based Assertions There are more assertions that are primarily used in testing views: -| Assertion | Purpose | -| ---------------------------------------------------------- | ------- | -| `assert_select_email` | Allows you to make assertions on the body of an e-mail. | -| `assert_select_encoded` | Allows you to make assertions on encoded HTML. It does this by un-encoding the contents of each element and then calling the block with all the un-encoded elements.| -| `css_select(selector)` or `css_select(element, selector)` | Returns an array of all the elements selected by the _selector_. In the second variant it first matches the base _element_ and tries to match the _selector_ expression on any of its children. If there are no matches both variants return an empty array.| +| Assertion | Purpose | +| --------------------------------------------------------- | ------- | +| `assert_select_email` | Allows you to make assertions on the body of an e-mail. | +| `assert_select_encoded` | Allows you to make assertions on encoded HTML. It does this by un-encoding the contents of each element and then calling the block with all the un-encoded elements.| +| `css_select(selector)` or `css_select(element, selector)` | Returns an array of all the elements selected by the _selector_. In the second variant it first matches the base _element_ and tries to match the _selector_ expression on any of its children. If there are no matches both variants return an empty array.| Here's an example of using `assert_select_email`: @@ -631,7 +669,7 @@ Integration tests are used to test the interaction among any number of controlle Unlike Unit and Functional tests, integration tests have to be explicitly created under the 'test/integration' folder within your application. Rails provides a generator to create an integration test skeleton for you. ```bash -$ rails generate integration_test user_flows +$ bin/rails generate integration_test user_flows exists test/integration/ create test/integration/user_flows_test.rb ``` @@ -642,12 +680,9 @@ Here's what a freshly-generated integration test looks like: require 'test_helper' class UserFlowsTest < ActionDispatch::IntegrationTest - fixtures :all - - # Replace this with your real tests. - test "the truth" do - assert true - end + # test "the truth" do + # assert true + # end end ``` @@ -680,22 +715,20 @@ A simple integration test that exercises multiple controllers: require 'test_helper' class UserFlowsTest < ActionDispatch::IntegrationTest - fixtures :users - test "login and browse site" do # login via https https! get "/login" assert_response :success - post_via_redirect "/login", username: users(:avs).username, password: users(:avs).password + post_via_redirect "/login", username: users(:david).username, password: users(:david).password assert_equal '/welcome', path - assert_equal 'Welcome avs!', flash[:notice] + assert_equal 'Welcome david!', flash[:notice] https!(false) - get "/posts/all" + get "/articles/all" assert_response :success - assert assigns(:products) + assert assigns(:articles) end end ``` @@ -708,21 +741,18 @@ Here's an example of multiple sessions and custom DSL in an integration test require 'test_helper' class UserFlowsTest < ActionDispatch::IntegrationTest - fixtures :users - test "login and browse site" do - - # User avs logs in - avs = login(:avs) + # User david logs in + david = login(:david) # User guest logs in guest = login(:guest) # Both are now available in different sessions - assert_equal 'Welcome avs!', avs.flash[:notice] + assert_equal 'Welcome david!', david.flash[:notice] assert_equal 'Welcome guest!', guest.flash[:notice] - # User avs can browse site - avs.browses_site + # User david can browse site + david.browses_site # User guest can browse site as well guest.browses_site @@ -731,96 +761,95 @@ class UserFlowsTest < ActionDispatch::IntegrationTest private - module CustomDsl - def browses_site - get "/products/all" - assert_response :success - assert assigns(:products) + module CustomDsl + def browses_site + get "/products/all" + assert_response :success + assert assigns(:products) + end 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', path - sess.https!(false) + 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 end ``` Rake Tasks for Running your Tests --------------------------------- -You don't need to set up and run your tests by hand on a test-by-test basis. Rails comes with a number of rake tasks to help in testing. The table below lists all rake tasks that come along in the default Rakefile when you initiate a Rails project. - -| Tasks | Description | -| ------------------------------- | ----------- | -| `rake test` | Runs all unit, functional and integration tests. You can also simply run `rake` as the _test_ target is the default.| -| `rake test:benchmark` | Benchmark the performance tests| -| `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:mailers` | Runs all the mailer tests from `test/mailers`| -| `rake test:models` | Runs all the model tests from `test/models`| -| `rake test:profile` | Profile the performance tests| -| `rake test:recent` | Tests recent changes| -| `rake test:uncommitted` | Runs all the tests which are uncommitted. Supports Subversion and Git| -| `rake test:units` | Runs all the unit tests from `test/models`, `test/helpers`, and `test/unit`| - - -Brief Note About `Test::Unit` +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` folder. You can also simply run `rake` as Rails will run all the 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` folder and resets the db | + + +A Brief Note About Minitest ----------------------------- -Ruby ships with a boat load of libraries. One little gem of a library is `Test::Unit`, a framework for unit testing in Ruby. All the basic assertions discussed above are actually defined in `Test::Unit::Assertions`. The class `ActiveSupport::TestCase` which we have been using in our unit and functional tests extends `Test::Unit::TestCase`, allowing -us to use all of the basic assertions in our tests. +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. -NOTE: For more information on `Test::Unit`, refer to [test/unit Documentation](http://ruby-doc.org/stdlib/libdoc/test/unit/rdoc/) +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 `Posts` controller: +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: ```ruby require 'test_helper' -class PostsControllerTest < ActionController::TestCase +class ArticlesControllerTest < ActionController::TestCase # called before every single test def setup - @post = posts(:one) + @article = articles(:one) end # called after every single test def teardown - # as we are re-initializing @post before every test + # 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 - @post = nil + @article = nil end - test "should show post" do - get :show, id: @post.id + test "should show article" do + get :show, id: @article.id assert_response :success end - test "should destroy post" do - assert_difference('Post.count', -1) do - delete :destroy, id: @post.id + test "should destroy article" do + assert_difference('Article.count', -1) do + delete :destroy, id: @article.id end - assert_redirected_to posts_path + assert_redirected_to articles_path end end ``` -Above, the `setup` method is called before each test and so `@post` 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: +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: * a block * a method (like in the earlier example) @@ -830,53 +859,58 @@ Above, the `setup` method is called before each test and so `@post` is available Let's see the earlier example by specifying `setup` callback by specifying a method name as a symbol: ```ruby -require '../test_helper' +require 'test_helper' -class PostsControllerTest < ActionController::TestCase +class ArticlesControllerTest < ActionController::TestCase # called before every single test - setup :initialize_post + setup :initialize_article # called after every single test def teardown - @post = nil + @article = nil end - test "should show post" do - get :show, id: @post.id + test "should show article" do + get :show, id: @article.id assert_response :success end - test "should update post" do - patch :update, id: @post.id, post: {} - assert_redirected_to post_path(assigns(:post)) + test "should update article" do + patch :update, id: @article.id, article: {} + assert_redirected_to article_path(assigns(:article)) end - test "should destroy post" do - assert_difference('Post.count', -1) do - delete :destroy, id: @post.id + test "should destroy article" do + assert_difference('Article.count', -1) do + delete :destroy, id: @article.id end - assert_redirected_to posts_path + assert_redirected_to articles_path end private - def initialize_post - @post = posts(:one) - end - + def initialize_article + @article = articles(:one) + end end ``` Testing Routes -------------- -Like everything else in your Rails application, it is recommended that you test your routes. An example test for a route in the default `show` action of `Posts` controller above should look like: +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 -test "should route to post" do - assert_routing '/posts/1', {controller: "posts", action: "show", id: "1"} +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 ``` @@ -887,7 +921,7 @@ Testing mailer classes requires some specific tools to do a thorough job. ### Keeping the Postman in Check -Your mailer classes — like every other part of your Rails application — should be tested to ensure that it is working as expected. +Your mailer classes - like every other part of your Rails application - should be tested to ensure that it is working as expected. The goals of testing your mailer classes are to ensure that: @@ -917,21 +951,25 @@ Here's a unit test to test a mailer named `UserMailer` whose action `invite` is require 'test_helper' class UserMailerTest < ActionMailer::TestCase - tests UserMailer test "invite" do - @expected.from = 'me@example.com' - @expected.to = 'friend@example.com' - @expected.subject = "You have been invited by #{@expected.from}" - @expected.body = read_fixture('invite') - @expected.date = Time.now - - assert_equal @expected.encoded, UserMailer.create_invite('me@example.com', 'friend@example.com', @expected.date).encoded + # Send the email, then test that it got queued + email = UserMailer.create_invite('me@example.com', + 'friend@example.com', Time.now).deliver_now + assert_not ActionMailer::Base.deliveries.empty? + + # Test the body of the sent email contains what we expect it to + assert_equal ['me@example.com'], email.from + assert_equal ['friend@example.com'], email.to + assert_equal 'You have been invited by me@example.com', email.subject + assert_equal read_fixture('invite').join, email.body.to_s end - end ``` -In this test, `@expected` is an instance of `TMail::Mail` that you can use in your tests. It is defined in `ActionMailer::TestCase`. The test above uses `@expected` to construct an email, which it then asserts with email created by the custom mailer. The `invite` fixture is the body of the email and is used as the sample content to assert against. The helper `read_fixture` is used to read in the content from this file. +In the test we send the email and store the returned object in the `email` +variable. We then ensure that it was sent (the first assert), then, in the +second batch of assertions, we ensure that the email does indeed contain what we +expect. The helper `read_fixture` is used to read in the content from this file. Here's the content of the `invite` fixture: @@ -943,9 +981,17 @@ You have been invited. Cheers! ``` -This is the right time to understand a little more about writing tests for your mailers. The line `ActionMailer::Base.delivery_method = :test` in `config/environments/test.rb` sets the delivery method to test mode so that email will not actually be delivered (useful to avoid spamming your users while testing) but instead it will be appended to an array (`ActionMailer::Base.deliveries`). +This is the right time to understand a little more about writing tests for your +mailers. The line `ActionMailer::Base.delivery_method = :test` in +`config/environments/test.rb` sets the delivery method to test mode so that +email will not actually be delivered (useful to avoid spamming your users while +testing) but instead it will be appended to an array +(`ActionMailer::Base.deliveries`). -However often in unit tests, mails will not actually be sent, simply constructed, as in the example above, where the precise content of the email is checked against what it should be. +NOTE: The `ActionMailer::Base.deliveries` array is only reset automatically in +`ActionMailer::TestCase` tests. If you want to have a clean slate outside Action +Mailer tests, you can reset it manually with: +`ActionMailer::Base.deliveries.clear` ### Functional Testing @@ -963,7 +1009,102 @@ class UserControllerTest < ActionController::TestCase assert_equal "You have been invited by me@example.com", invite_email.subject assert_equal 'friend@example.com', invite_email.to[0] - assert_match(/Hi friend@example.com/, invite_email.body) + assert_match(/Hi friend@example.com/, invite_email.body.to_s) + end +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 +------------ + +Since your custom jobs can be queued at different levels inside your application, +you'll need to test both jobs themselves (their behavior when they get enqueued) +and that other entities correctly enqueue them. + +### A Basic Test Case + +By default, when you generate a job, an associated test will be generated as well +under the `test/jobs` directory. Here's an example test with a billing job: + +```ruby +require 'test_helper' + +class BillingJobTest < ActiveJob::TestCase + test 'that account is charged' do + BillingJob.perform_now(account, product) + assert account.reload.charged_for?(product) + end +end +``` + +This test is pretty simple and only asserts that the job get the work done +as expected. + +By default, `ActiveJob::TestCase` will set the queue adapter to `:test` so that +your jobs are performed inline. It will also ensure that all previously performed +and enqueued jobs are cleared before any test run so you can safely assume that +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. | + +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 +the custom assertions provided by Active Job are pretty useful. For instance, +within a model: + +```ruby +require 'test_helper' + +class ProductTest < ActiveSupport::TestCase + test 'billing job scheduling' do + assert_enqueued_with(job: BillingJob) do + product.charge(account) + end end end ``` @@ -971,10 +1112,12 @@ end Other Testing Approaches ------------------------ -The built-in `test/unit` based testing is not the only way to test Rails applications. Rails developers have come up with a wide variety of other approaches and aids for testing, including: +The built-in `minitest` based testing is not the only way to test Rails applications. Rails developers have come up with a wide variety of other approaches and aids for testing, including: * [NullDB](http://avdi.org/projects/nulldb/), a way to speed up testing by avoiding database use. * [Factory Girl](https://github.com/thoughtbot/factory_girl/tree/master), a replacement for fixtures. -* [Machinist](https://github.com/notahat/machinist/tree/master), another replacement for fixtures. +* [Fixture Builder](https://github.com/rdy/fixture_builder), a tool that compiles Ruby factories into fixtures before a test run. +* [MiniTest::Spec Rails](https://github.com/metaskills/minitest-spec-rails), use the MiniTest::Spec DSL within your rails tests. * [Shoulda](http://www.thoughtbot.com/projects/shoulda), an extension to `test/unit` with additional helpers, macros, and assertions. * [RSpec](http://relishapp.com/rspec), a behavior-driven development framework +* [Capybara](http://jnicklas.github.com/capybara/), Acceptance test framework for web applications |