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diff --git a/guides/source/testing.md b/guides/source/testing.md index aa37115d14..58524fd6c5 100644 --- a/guides/source/testing.md +++ b/guides/source/testing.md @@ -1,3 +1,5 @@ +**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.** + A Guide to Testing Rails Applications ===================================== @@ -23,17 +25,11 @@ Rails tests can also simulate browser requests and thus you can test your applic Introduction to Testing ----------------------- -Testing support was woven into the Rails fabric from the beginning. It wasn't an "oh! let's bolt on support for running tests because they're new and cool" epiphany. Just about every Rails application interacts heavily with a database and, as a result, your tests will need a database to interact with as well. To write efficient tests, you'll need to understand how to set up this database and populate it with sample data. - -### The Test Environment - -By default, every Rails application has three environments: development, test, and production. The database for each one of them is configured in `config/database.yml`. - -A dedicated test database allows you to set up and interact with test data in isolation. Tests can mangle test data with confidence, that won't touch the data in the development or production databases. +Testing support was woven into the Rails fabric from the beginning. It wasn't an "oh! let's bolt on support for running tests because they're new and cool" epiphany. ### Rails Sets up for Testing from the Word Go -Rails creates a `test` folder for you as soon as you create a Rails project using `rails new` _application_name_. If you list the contents of this folder then you shall see: +Rails creates a `test` directory for you as soon as you create a Rails project using `rails new` _application_name_. If you list the contents of this directory then you shall see: ```bash $ ls -F test @@ -41,120 +37,42 @@ controllers/ helpers/ mailers/ test_helper.rb fixtures/ integration/ models/ ``` -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. +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. There is also a directory for testing your mailers and one for testing view helpers. -Fixtures are a way of organizing test data; they reside in the `fixtures` folder. +Fixtures are a way of organizing test data; they reside in the `fixtures` directory. 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. - -#### What Are Fixtures? - -_Fixtures_ is a fancy word for sample data. Fixtures allow you to populate your testing database with predefined data before your tests run. Fixtures are database independent written in YAML. There is one file per model. - -You'll find fixtures under your `test/fixtures` directory. When you run `rails generate model` to create a new model fixture stubs will be automatically created and placed in this directory. - -#### YAML - -YAML-formatted fixtures are a very human-friendly way to describe your sample data. These types of fixtures have the **.yml** file extension (as in `users.yml`). - -Here's a sample YAML fixture file: - -```yaml -# lo & behold! I am a YAML comment! -david: - name: David Heinemeier Hansson - birthday: 1979-10-15 - profession: Systems development - -steve: - 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. 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 -``` - -#### ERB'in It Up - -ERB allows you to embed Ruby code within templates. The YAML fixture format is pre-processed with ERB when Rails loads fixtures. This allows you to use Ruby to help you generate some sample data. For example, the following code generates a thousand users: - -```erb -<% 1000.times do |n| %> -user_<%= 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 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 -* Dump the fixture data into a variable in case you want to access it directly - -#### Fixtures are Active Record objects - -Fixtures are instances of Active Record. As mentioned in point #3 above, you can access the object directly because it is automatically setup as a local variable of the test case. For example: - -```ruby -# this will return the User object for the fixture named david -users(:david) -# this will return the property for david called id -users(:david).id - -# one can also access methods available on the User class -email(david.girlfriend.email, david.location_tonight) -``` +### The Test Environment -Unit Testing your Models ------------------------- +By default, every Rails application has three environments: development, test, and production. -In Rails, models tests are what you write to test your models. +Each environment's configuration can be modified similarly. In this case, we can modify our test environment by changing the options found in `config/environments/test.rb`. -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. +NOTE: Your tests are run under `RAILS_ENV=test`. -NOTE: For more information on Rails <i>scaffolding</i>, refer to [Getting Started with Rails](getting_started.html) +### Rails meets Minitest -When you use `rails generate scaffold`, for a resource among other things it creates a test stub in the `test/models` folder: +If you remember when you used the `rails generate model` command from the +[Getting Started with Rails](getting_started.html) guide. We created our first +model among other things it created test stubs in the `test` directory: ```bash -$ rails generate scaffold post title:string body:text +$ bin/rails generate model 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 +class ArticleTest < ActiveSupport::TestCase # test "the truth" do # assert true # end @@ -167,18 +85,18 @@ A line by line examination of this file will help get you oriented to Rails test 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. +By requiring this file, `test_helper.rb` the default configuration to run our tests is loaded. We will include this with all the tests we write, 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`. Later in this guide, you'll see some of the methods it gives you. -Any method defined within a class inherited from `MiniTest::Unit::TestCase` -(which is the superclass of `ActiveSupport::TestCase`) 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, methods defined as `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 `MiniTest::Unit` test with method names prefixed with `test_`. So, +Rails also 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 you don't have to worry about naming the methods, and you can write something like: ```ruby test "the truth" do @@ -186,7 +104,7 @@ test "the truth" do end ``` -acts as if you had written +Which is approximately the same as writing this: ```ruby def test_the_truth @@ -194,85 +112,57 @@ def test_the_truth end ``` -only the `test` macro allows a more readable test name. You can still use regular method definitions though. +However only the `test` macro allows a more readable test name. You can still use regular method definitions though. -NOTE: The method name is generated by replacing spaces with underscores. The result does not need to be a valid Ruby identifier though, the name may contain punctuation characters etc. That's because in Ruby technically any string may be a method name. Odd ones need `define_method` and `send` calls, but formally there's no restriction. +NOTE: The method name is generated by replacing spaces with underscores. The result does not need to be a valid Ruby identifier though, the name may contain punctuation characters etc. That's because in Ruby technically any string may be a method name. This may require use of `define_method` and `send` calls to function properly, but formally there's little restriction on the name. + +Next, let's look at our first assertion: ```ruby assert true ``` -This line of code is called an _assertion_. An assertion is a line of code that evaluates an object (or expression) for expected results. For example, an assertion can check: +An assertion is a line of code that evaluates an object (or expression) for expected results. For example, an assertion can check: * does this value = that value? * is this object nil? * does this line of code throw an exception? * is the user's password greater than 5 characters? -Every test contains one or more assertions. Only when all the assertions are successful will the test pass. - -### Maintaining the test database schema - -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 `rake test` command. - -```bash -$ rake test test/models/post_test.rb -. - -Finished tests in 0.009262s, 107.9680 tests/s, 107.9680 assertions/s. - -1 tests, 1 assertions, 0 failures, 0 errors, 0 skips -``` - -You can also run a particular test method from the test case by running the test and providing the `test method name`. - -```bash -$ rake test test/models/post_test.rb test_the_truth -. - -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. +Every test must contain at least one assertion, with no restriction as to how many assertions are allowed. Only when all the assertions are successful will the test pass. -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. +#### Your first failing test -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_not 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. +Let us run this newly added test (where `6` is the number of line where the test is defined). ```bash -$ rake test test/models/post_test.rb test_should_not_save_post_without_title +$ bin/rails test test/models/article_test.rb:6 F 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]: +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, 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: +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 that 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_not 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 ``` @@ -280,14 +170,14 @@ 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 +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 ``` @@ -295,7 +185,7 @@ end Now the test should pass. Let us verify by running the test again: ```bash -$ rake test test/models/post_test.rb test_should_not_save_post_without_title +$ bin/rails test test/models/article_test.rb:6 . Finished tests in 0.047721s, 20.9551 tests/s, 20.9551 assertions/s. @@ -303,9 +193,13 @@ 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). +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)](http://c2.com/cgi/wiki?TestDrivenDevelopment). -TIP: Many Rails developers practice _Test-Driven Development_ (TDD). This is an excellent way to build up a test suite that exercises every part of your application. TDD is beyond the scope of this guide, but one place to start is with [15 TDD steps to create a Rails application](http://andrzejonsoftware.blogspot.com/2007/05/15-tdd-steps-to-create-rails.html). +#### What an error looks like To see how an error gets reported, here's a test containing an error: @@ -320,44 +214,58 @@ end Now you can see even more output in the console from running the tests: ```bash -$ rake test test/models/post_test.rb test_should_report_error +$ bin/rails test test/models/article_test.rb E 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:0x007fe32e24afe0> - test/models/post_test.rb:10:in `block in <class:PostTest>' +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, 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. +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 random order. The +[`config.active_support.test_order` option](configuring.html#configuring-active-support) +can be used to configure test 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: +backtrace. Simply set the `-b` (or `--backtrace`) argument to enable this behavior: ```bash -$ BACKTRACE=1 rake test test/models/post_test.rb +$ bin/rails test -b test/models/article_test.rb ``` -### What to Include in Your Unit Tests +If we want this test to pass we can modify it to use `assert_raises` like so: -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. +```ruby +test "should report error" do + # some_undefined_variable is not defined elsewhere in the test case + assert_raises(NameError) do + some_undefined_variable + end +end +``` + +This test should now pass. ### 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 an extract of the assertions you can use with `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. +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 | | ---------------------------------------------------------------- | ------- | @@ -369,48 +277,368 @@ Here's an extract of the assertions you can use with `minitest`, the default tes | `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_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_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( expected, actual, [delta], [msg] )` | Ensures that the numbers `expected` and `actual` are within `delta` of each other.| +| `assert_not_in_delta( expected, 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_kind_of( class, obj, [msg] )` | Ensures that `obj` is an instance of `class` or is descending from it.| | `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 a 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 | | --------------------------------------------------------------------------------- | ------- | | `assert_difference(expressions, difference = 1, message = nil) {...}` | Test numeric difference between the return value of an expression as a result of what is evaluated in the yielded block.| -| `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_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. 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.| +| `assert_redirected_to(options = {}, message=nil)` | Asserts 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`.| You'll see the usage of some of these assertions in the next chapter. +### A Brief Note About Test Cases + +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` +* `ActionMailer::TestCase` +* `ActionView::TestCase` +* `ActionDispatch::IntegrationTest` +* `ActiveJob::TestCase` + +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 [its +documentation](http://docs.seattlerb.org/minitest). + +### The Rails Test Runner + +We can run all of our tests at once by using the `rails test` command. + +Or we can run a single test by passing the `rails test` command the filename containing the test cases. + +```bash +$ bin/rails test test/models/article_test.rb +. + +Finished tests in 0.009262s, 107.9680 tests/s, 107.9680 assertions/s. + +1 tests, 1 assertions, 0 failures, 0 errors, 0 skips +``` + +This will run all test methods from the test case. + +You can also run a particular test method from the test case by providing the +`-n` or `--name` flag and the test's method name. + +```bash +$ bin/rails test test/models/article_test.rb -n test_the_truth +. + +Finished tests in 0.009064s, 110.3266 tests/s, 110.3266 assertions/s. + +1 tests, 1 assertions, 0 failures, 0 errors, 0 skips +``` + +You can also run a test at a specific line by providing the line number. + +```bash +$ bin/rails test test/models/post_test.rb:44 # run specific test and line +``` + +You can also run an entire directory of tests by providing the path to the directory. + +```bash +$ bin/rails test test/controllers # run all tests from specific directory +``` + + +The Test Database +----------------- + +Just about every Rails application interacts heavily with a database and, as a result, your tests will need a database to interact with as well. To write efficient tests, you'll need to understand how to set up this database and populate it with sample data. + +By default, every Rails application has three environments: development, test, and production. The database for each one of them is configured in `config/database.yml`. + +A dedicated test database allows you to set up and interact with test data in isolation. This way your tests can mangle test data with confidence, without worrying about the data in the development or production databases. + + +### Maintaining the test database schema + +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. Usually this indicates that your schema is not fully migrated. Running +the migrations against the development database (`bin/rake db:migrate`) will +bring the schema up to date. + +NOTE: If existing migrations required modifications, the test database needs to +be rebuilt. This can be done by executing `bin/rake db:test:prepare`. + +### 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. +You can find comprehensive documentation in the [Fixtures API documentation](http://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html). + +#### What Are Fixtures? + +_Fixtures_ is a fancy word for sample data. Fixtures allow you to populate your testing database with predefined data before your tests run. Fixtures are database independent and written in YAML. There is one file per model. + +You'll find fixtures under your `test/fixtures` directory. When you run `rails generate model` to create a new model, Rails automatically creates fixture stubs in this directory. + +#### YAML + +YAML-formatted fixtures are a human-friendly way to describe your sample data. These types of fixtures have the **.yml** file extension (as in `users.yml`). + +Here's a sample YAML fixture file: + +```yaml +# lo & behold! I am a YAML comment! +david: + name: David Heinemeier Hansson + birthday: 1979-10-15 + profession: Systems development + +steve: + 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 line. You can place comments in a fixture file by using the # character in the first column. + +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 +``` + +Notice the `category` key of the `one` article found in `fixtures/articles.yml` has a value of `about`. This tells Rails to load the category `about` found in `fixtures/categories.yml`. + +NOTE: For associations to reference one another by name, you cannot specify the `id:` attribute on the associated fixtures. Rails will auto assign a primary key to be consistent between runs. 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 + +ERB allows you to embed Ruby code within templates. The YAML fixture format is pre-processed with ERB when Rails loads fixtures. This allows you to use Ruby to help you generate some sample data. For example, the following code generates a thousand users: + +```erb +<% 1000.times do |n| %> +user_<%= n %>: + username: <%= "user#{n}" %> + email: <%= "user#{n}@example.com" %> +<% end %> +``` + +#### Fixtures in Action + +Rails automatically loads all fixtures from the `test/fixtures` directory by +default. Loading involves three steps: + +1. Remove any existing data from the table corresponding to the fixture +2. Load the fixture data into the table +3. Dump the fixture data into a method in case you want to access it directly + +TIP: In order to remove existing data from the database, Rails tries to disable referential integrity triggers (like foreign keys and check constraints). If you are getting annoying permission errors on running tests, make sure the database user has privilege to disable these triggers in testing environment. (In PostgreSQL, only superusers can disable all triggers. Read more about PostgreSQL permissions [here](http://blog.endpoint.com/2012/10/postgres-system-triggers-error.html)). + +#### Fixtures are Active Record objects + +Fixtures are instances of Active Record. As mentioned in point #3 above, you can access the object directly because it is automatically available as a method whose scope is local of the test case. For example: + +```ruby +# this will return the User object for the fixture named david +users(:david) + +# this will return the property for david called id +users(:david).id + +# one can also access methods available on the User class +email(david.partner.email, david.location_tonight) +``` + +To get multiple fixtures at once, you can pass in a list of fixture names. For example: + +```ruby +# this will return an array containing the fixtures david and steve +users(:david, :steve) +``` + + +Model Testing +------------- + +Model tests are used to test the various models of your application. + +Rails model tests are stored under the `test/models` directory. Rails provides +a generator to create a model test skeleton for you. + +```bash +$ bin/rails generate test_unit:model article title:string body:text +create test/models/article_test.rb +create test/fixtures/articles.yml +``` + +Model tests don't have their own superclass like `ActionMailer::TestCase` instead they inherit from `ActiveSupport::TestCase`. + + +Integration Testing +------------------- + +Integration tests are used to test how various parts of your application interact. They are generally used to test important workflows within your application. + +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 + exists test/integration/ + create test/integration/user_flows_test.rb +``` + +Here's what a freshly-generated integration test looks like: + +```ruby +require 'test_helper' + +class UserFlowsTest < ActionDispatch::IntegrationTest + # test "the truth" do + # assert true + # end +end +``` + +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, 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. + +For dealing with the integration test runner, see [`ActionDispatch::Integration::Runner`](http://api.rubyonrails.org/classes/ActionDispatch/Integration/Runner.html). + +When performing requests, you will have [`ActionDispatch::Integration::RequestHelpers`](http://api.rubyonrails.org/classes/ActionDispatch/Integration/RequestHelpers.html) available for your use. + +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. + +### Implementing an integration test + +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. + +We'll start by generating our integration test skeleton: + +```bash +$ bin/rails generate integration_test blog_flow +``` + +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 +``` + +Now let's open that file and write our first assertion: + +```ruby +require 'test_helper' + +class BlogFlowTest < ActionDispatch::IntegrationTest + test "can see the welcome page" do + get "/" + assert_select "h1", "Welcome#index" + end +end +``` + +If you remember from earlier in the "Testing Views" section we covered `assert_select` to query the resulting HTML of a request. + +When visit our root path, we should see `welcome/index.html.erb` rendered for the view. So this assertion should pass. + +#### Creating articles integration + +How about testing our ability to create a new article in our blog and see the resulting article. + +```ruby +test "can create an article" do + get "/articles/new" + assert_response :success + + post "/articles", + params: { article: { title: "can create", body: "article successfully." } } + assert_response :redirect + follow_redirect! + assert_response :success + assert_select "p", "Title:\n can create" +end +``` + +Let's break this test down so we can understand it. + +We start by calling the `:new` action on our Articles controller. This response should be successful. + +After this we make a post request to the `:create` action of our Articles controller: + +```ruby +post "/articles", + params: { article: { title: "can create", body: "article successfully." } } +assert_response :redirect +follow_redirect! +``` + +The two lines following the request are to handle the redirect we setup when creating a new article. + +NOTE: Don't forget to call `follow_redirect!` if you plan to make subsequent requests after a redirect is made. + +Finally we can assert that our response was successful and our new article is readable on the page. + +#### 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 editing comments. Integration tests are a great place to experiment with all kinds of use-cases for our applications. + + 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 @@ -422,52 +650,86 @@ 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. +The easiest way to see functional tests in action is to generate a controller +scaffold: + +```bash +$ bin/rails generate scaffold_controller article title:string body:test +... +create app/controllers/articles_controller.rb +... +invoke test_unit +create test/controllers/articles_controller_test.rb +... +``` + +This will generate the controller code and tests for an `Article` resource. +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`. +If you already have a controller and just want to generate the test scaffold code for +each of the seven default actions, you can use the following command: + +```bash +$ bin/rails generate test_unit:scaffold article +... +invoke test_unit +create test/controllers/articles_controller_test.rb +... +``` + +Let me take you through one such test, `test_should_get_index` from the file `articles_controller_test.rb`. ```ruby -class PostsControllerTest < ActionController::TestCase +# articles_controller_test.rb +class ArticlesControllerTest < ActionDispatch::IntegrationTest test "should get index" do - get :index + get '/articles' assert_response :success - assert_not_nil assigns(:posts) + assert_includes @response.body, '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 the right response body has been generated. 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 session variables to pass along with the request. -* An optional hash of flash values. +* The action of the controller you are requesting. + This can be in the form of a string or a route (i.e. `articles_url`). + +* `params`: option with a hash of request parameters to pass into the action + (e.g. query string parameters or article variables). + +* `session`: option with a hash of session variables to pass along with the request. + +* `flash`: option with a hash of flash values. + +All the keyword arguments are optional. Example: Calling the `:show` action, passing an `id` of 12 as the `params` and setting a `user_id` of 5 in the session: ```ruby -get(:show, {'id' => "12"}, {'user_id' => 5}) +get(:show, params: { id: 12 }, session: { user_id: 5 }) ``` Another example: Calling the `:view` action, passing an `id` of 12 as the `params`, this time with no session, but with a flash message. ```ruby -get(:view, {'id' => '12'}, nil, {'message' => 'booya!'}) +get(view_url, params: { id: 12 }, flash: { 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 '/article', params: { article: { title: 'Some title' } } end - assert_redirected_to post_path(assigns(:post)) + assert_redirected_to article_path(Article.last) end ``` @@ -484,28 +746,39 @@ 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 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. + +### Testing XHR (AJAX) requests -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. +To test AJAX requests, you can specify the `xhr: true` option to `get`, `post`, +`patch`, `put`, and `delete` methods: + +```ruby +test "ajax request" do + article = articles(:first) + get article_url(article), xhr: true + + assert_equal 'hello world', @response.body + assert_equal "text/javascript", @response.content_type +end +``` -### The Four Hashes of the Apocalypse +### The Three 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 3 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. -* `flash` - Any objects living in the flash. -* `session` - Any object living in session variables. +* `cookies` - Any cookies that are set +* `flash` - Any objects living in the flash +* `session` - Any object living in session variables -As is the case with normal Hash objects, you can access the values by referencing the keys by string. You can also reference them by symbol name, except for `assigns`. For example: +As is the case with normal Hash objects, you can access the values by referencing the keys by string. You can also reference them by symbol name. For example: ```ruby flash["gordon"] flash[:gordon] session["shmession"] session[:shmession] cookies["are_good_for_u"] cookies[:are_good_for_u] - -# Because you can't use assigns[:something] for historical reasons: -assigns["something"] assigns(:something) ``` ### Instance Variables Available @@ -513,8 +786,8 @@ 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 @@ -526,382 +799,303 @@ 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 +get articles_url # 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 +post article_url # simulate the request with custom env variable ``` -### Testing Templates and Layouts +### Testing `flash` notices -If you want to make sure that the response rendered the correct template and layout, you can use the `assert_template` -method: +If you remember from earlier one of the Three Hashes of the Apocalypse was `flash`. -```ruby -test "index should render correct template and layout" do - get :index - assert_template :index - assert_template layout: "layouts/application" -end -``` +We want to add a `flash` message to our blog application whenever someone +successfully creates a new Article. -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, +Let's start by adding this assertion to our `test_should_create_article` test: ```ruby -assert_template layout: "application" +test "should create article" do + assert_difference('Article.count') do + post article_url, params: { article: { title: 'Some title' } } + end + + assert_redirected_to article_path(Article.last) + assert_equal 'Article was successfully created.', flash[:notice] +end ``` -will not work. +If we run our test now, we should see a failure: -If your view renders any partial, when asserting for the layout, you have to assert for the partial at the same time. -Otherwise, assertion will fail. +```bash +$ bin/rails test test/controllers/articles_controller_test.rb test_should_create_article +Run options: -n test_should_create_article --seed 32266 -Hence: +# Running: -```ruby -test "new should render correct layout" do - get :new - assert_template layout: "layouts/application", partial: "_form" -end -``` +F -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. +Finished in 0.114870s, 8.7055 runs/s, 34.8220 assertions/s. -### A Fuller Functional Test Example + 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 +``` -Here's another example that uses `flash`, `assert_redirected_to`, and `assert_difference`: +Let's implement the flash message now in our controller. Our `:create` action should now look like this: ```ruby -test "should create post" do - assert_difference('Post.count') do - post :create, post: {title: 'Hi', body: 'This is my first post.'} +def create + @article = Article.new(article_params) + + if @article.save + flash[:notice] = 'Article was successfully created.' + redirect_to @article + else + render 'new' end - assert_redirected_to post_path(assigns(:post)) - assert_equal 'Post was successfully created.', flash[:notice] end ``` -### Testing Views +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/rails 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, but this is now deprecated in favor of `assert_select`. +# Running: -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. +Finished in 0.081972s, 12.1993 runs/s, 48.7972 assertions/s. -`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. +1 runs, 4 assertions, 0 failures, 0 errors, 0 skips +``` -For example, you could verify the contents on the title element in your response with: +### Putting it together -```ruby -assert_select 'title', "Welcome to Rails Testing Guide" -``` +At this point our Articles controller tests the `:index` as well as `:new` and `:create` actions. What about dealing with existing data? -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: +Let's write a test for the `:show` action: ```ruby -assert_select 'ul.navigation' do - assert_select 'li.menu_item' +test "should show article" do + article = articles(:one) + get '/article', params: { id: article.id } + assert_response :success 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. +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 -assert_select "ol" do |elements| - elements.each do |element| - assert_select element, "li", 4 +test "should destroy article" do + article = articles(:one) + assert_difference('Article.count', -1) do + delete article_url(article) end -end -assert_select "ol" do - assert_select "li", 8 + assert_redirected_to articles_path 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). - -#### 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.| - -Here's an example of using `assert_select_email`: +We can also add a test for updating an existing Article. ```ruby -assert_select_email do - assert_select 'small', 'Please click the "Unsubscribe" link if you want to opt-out.' +test "should update article" do + article = articles(:one) + patch '/article', params: { id: article.id, article: { title: "updated" } } + assert_redirected_to article_path(article) end ``` -Integration Testing -------------------- +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`. -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. - -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 - exists test/integration/ - create test/integration/user_flows_test.rb -``` - -Here's what a freshly-generated integration test looks like: +Our test should now look something like this, disregard the other tests we're leaving them out for brevity. ```ruby require 'test_helper' -class UserFlowsTest < ActionDispatch::IntegrationTest - # test "the truth" do - # assert true - # end -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. +class ArticlesControllerTest < ActionDispatch::IntegrationTest + # called before every single test + setup do + @article = articles(:one) + end -### Helpers Available for Integration Tests + # 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 -In addition to the standard testing helpers, there are some additional helpers available to integration tests: + test "should show article" do + # Reuse the @article instance variable from setup + get article_url(@article) + assert_response :success + end -| 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.| + test "should destroy article" do + assert_difference('Article.count', -1) do + delete article_url(@article) + end -### Integration Testing Examples + assert_redirected_to articles_path + end -A simple integration test that exercises multiple controllers: + test "should update article" do + patch article_url(@article), params: { article: { title: "updated" } } + assert_redirected_to article_path(@article) + end +end +``` -```ruby -require 'test_helper' +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. -class UserFlowsTest < ActionDispatch::IntegrationTest - fixtures :users +### Test helpers - test "login and browse site" do - # login via https - https! - get "/login" - assert_response :success +To avoid code duplication, you can add your own test helpers. +Sign in helper can be a good example: - post_via_redirect "/login", username: users(:david).username, password: users(:david).password - assert_equal '/welcome', path - assert_equal 'Welcome david!', flash[:notice] +```ruby +test/test_helper.rb - https!(false) - get "/posts/all" - assert_response :success - assert assigns(:products) +module SignInHelper + def sign_in(user) + session[:user_id] = user.id end end -``` - -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. -Here's an example of multiple sessions and custom DSL in an integration test +class ActionDispatch::IntegrationTest + include SignInHelper +end +``` ```ruby require 'test_helper' -class UserFlowsTest < ActionDispatch::IntegrationTest - fixtures :users - - test "login and browse site" do +class ProfileControllerTest < ActionDispatch::IntegrationTest - # User david logs in - david = login(:david) - # User guest logs in - guest = login(:guest) + test "should show profile" do + # helper is now reusable from any controller test case + sign_in users(:david) - # 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 + get profile_url + assert_response :success 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 ---------------------------------- - -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 commands to help in testing. -The table below lists all commands that come along in the default Rakefile -when you initiate a Rails project. +Testing Routes +-------------- -| Tasks | Description | -| ----------------------- | ----------- | -| `rake test` | Runs all unit, functional and integration tests. 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: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:all` | Runs all tests quickly by merging all types and not resetting db | -| `rake test:all:db` | Runs all tests quickly by merging all types and resetting db | +Like everything else in your Rails application, you can test your routes. +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). -Brief Note About `MiniTest` ------------------------------ +Testing Views +------------- -Ruby ships with a boat load of libraries. Ruby 1.8 provides `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. +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. Like route tests, view tests reside in `test/controllers/` or are part of controller tests. The `assert_select` method allows you to query HTML elements of the response by using a simple yet powerful syntax. -Ruby 1.9 introduced `MiniTest`, an updated version of `Test::Unit` which provides a backwards compatible API for `Test::Unit`. You could also use `MiniTest` in Ruby 1.8 by installing the `minitest` gem. +There are two forms of `assert_select`: -NOTE: For more information on `Test::Unit`, refer to [test/unit Documentation](http://ruby-doc.org/stdlib/libdoc/test/unit/rdoc/) -For more information on `MiniTest`, refer to [Minitest](http://www.ruby-doc.org/stdlib-1.9.3/libdoc/minitest/unit/rdoc/) +`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. -Setup and Teardown ------------------- +`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. -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: +For example, you could verify the contents on the title element in your response with: ```ruby -require 'test_helper' +assert_select 'title', "Welcome to Rails Testing Guide" +``` -class PostsControllerTest < ActionController::TestCase +You can also use nested `assert_select` blocks for deeper investigation. - # called before every single test - def setup - @post = posts(:one) - end +In the following example, the inner `assert_select` for `li.menu_item` runs +within the collection of elements selected by the outer block: - # called after every single test - def teardown - # as we are re-initializing @post 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 - end +```ruby +assert_select 'ul.navigation' do + assert_select 'li.menu_item' +end +``` - test "should show post" do - get :show, id: @post.id - assert_response :success - end +A collection of selected elements may be iterated through so that `assert_select` may be called separately for each element. - test "should destroy post" do - assert_difference('Post.count', -1) do - delete :destroy, id: @post.id - end +For example if the response contains two ordered lists, each with four nested list elements then the following tests will both pass. - assert_redirected_to posts_path +```ruby +assert_select "ol" do |elements| + elements.each do |element| + assert_select element, "li", 4 end +end +assert_select "ol" do + assert_select "li", 8 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: - -* a block -* a method (like in the earlier example) -* a method name as a symbol -* a lambda - -Let's see the earlier example by specifying `setup` callback by specifying a method name as a symbol: +This assertion is quite powerful. For more advanced usage, refer to its [documentation](http://www.rubydoc.info/github/rails/rails-dom-testing). -```ruby -require 'test_helper' +#### Additional View-Based Assertions -class PostsControllerTest < ActionController::TestCase +There are more assertions that are primarily used in testing views: - # called before every single test - setup :initialize_post +| 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.| - # called after every single test - def teardown - @post = nil - end +Here's an example of using `assert_select_email`: - test "should show post" do - get :show, id: @post.id - assert_response :success - end +```ruby +assert_select_email do + assert_select 'small', 'Please click the "Unsubscribe" link if you want to opt-out.' +end +``` - test "should update post" do - patch :update, id: @post.id, post: {} - assert_redirected_to post_path(assigns(:post)) - end +Testing Helpers +--------------- - test "should destroy post" do - assert_difference('Post.count', -1) do - delete :destroy, id: @post.id - end +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. - assert_redirected_to posts_path - end +A helper test looks like so: - private +```ruby +require 'test_helper' - def initialize_post - @post = posts(:one) - end +class UserHelperTest < ActionView::TestCase 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: +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 -test "should route to post" do - assert_routing '/posts/1', {controller: "posts", action: "show", id: "1"} +class UserHelperTest < ActionView::TestCase + 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 Your Mailers -------------------- @@ -909,7 +1103,7 @@ 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 they are working as expected. The goals of testing your mailer classes are to ensure that: @@ -940,10 +1134,14 @@ require 'test_helper' class UserMailerTest < ActionMailer::TestCase test "invite" do - # Send the email, then test that it got queued + # Create the email and store it for further assertions email = UserMailer.create_invite('me@example.com', - 'friend@example.com', Time.now).deliver - assert_not ActionMailer::Base.deliveries.empty? + 'friend@example.com', Time.now) + + # Send the email, then test that it got queued + assert_emails 1 do + email.deliver_now + end # Test the body of the sent email contains what we expect it to assert_equal ['me@example.com'], email.from @@ -988,70 +1186,89 @@ Functional testing for mailers involves more than just checking that the email b ```ruby require 'test_helper' -class UserControllerTest < ActionController::TestCase +class UserControllerTest < ActionDispatch::IntegrationTest test "invite friend" do assert_difference 'ActionMailer::Base.deliveries.size', +1 do - post :invite_friend, email: 'friend@example.com' + post invite_friend_url, params: { email: 'friend@example.com' } end invite_email = ActionMailer::Base.deliveries.last 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 ---------------- +Testing Jobs +------------ -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. Rails provides a generator which -generates both the helper and the test file: +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. -```bash -$ rails generate helper User - create app/helpers/user_helper.rb - invoke test_unit - create test/helpers/user_helper_test.rb -``` +### A Basic Test Case -The generated test file contains the following code: +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 UserHelperTest < ActionView::TestCase +class BillingJobTest < ActiveJob::TestCase + test 'that account is charged' do + BillingJob.perform_now(account, product) + assert account.reload.charged_for?(product) + end 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: +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. 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 +the custom assertions provided by Active Job are pretty useful. For instance, +within a model: ```ruby -class UserHelperTest < ActionView::TestCase - include UserHelper +require 'test_helper' - test "should return the user name" do - # ... +class ProductTest < ActiveJob::TestCase + test 'billing job scheduling' do + assert_enqueued_with(job: BillingJob) do + product.charge(account) + end 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 Time-Dependent Code +--------------------------- -Other Testing Approaches ------------------------- +Rails provides inbuilt helper methods that enable you to assert that your time-sensitve code works as expected. -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: +Here is an example using the [`travel_to`](http://api.rubyonrails.org/classes/ActiveSupport/Testing/TimeHelpers.html#method-i-travel_to) helper: + +```ruby +# Lets say that a user is eligible for gifting a month after they register. +user = User.create(name: 'Gaurish', activation_date: Date.new(2004, 10, 24)) +assert_not user.applicable_for_gifting? +travel_to Date.new(2004, 11, 24) do + assert_equal Date.new(2004, 10, 24), user.activation_date # inside the travel_to block `Date.current` is mocked + assert user.applicable_for_gifting? +end +assert_equal Date.new(2004, 10, 24), user.activation_date # The change was visible only inside the `travel_to` block. +``` -* [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 +Please see [`ActiveSupport::TimeHelpers` API Documentation](http://api.rubyonrails.org/classes/ActiveSupport/Testing/TimeHelpers.html) +for in-depth information about the available time helpers. |