diff options
Diffstat (limited to 'guides/source/testing.md')
| -rw-r--r-- | guides/source/testing.md | 176 |
1 files changed, 98 insertions, 78 deletions
diff --git a/guides/source/testing.md b/guides/source/testing.md index 7b206f8b4a..70061dc815 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/ 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 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. Fixtures are a way of organizing test data; they reside in the `fixtures` folder. @@ -140,10 +139,9 @@ The default test stub in `test/unit/post_test.rb` looks like this: require 'test_helper' class PostTest < ActiveSupport::TestCase - # Replace this with your real tests. - test "the truth" do - assert true - end + # test "the truth" do + # assert true + # end end ``` @@ -224,34 +222,30 @@ TIP: You can see all these rake tasks and their descriptions by running `rake -- ### 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 `rails test` command. ```bash -$ ruby -Itest test/unit/post_test.rb - -Loaded suite models/post_test -Started +$ rails test test/models/post_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 using `-n` switch with the `test method name`. ```bash -$ ruby -Itest test/unit/post_test.rb -n test_the_truth - -Loaded suite unit/post_test -Started +$ rails test test/models/post_test.rb -n 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. @@ -266,17 +260,16 @@ end Let us run this newly added test. ```bash -$ ruby -Itest test/unit/post_test.rb -n test_should_not_save_post_without_title -Loaded suite -e -Started +$ rails test test/models/post_test.rb -n test_should_not_save_post_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_post_without_title(PostTest) [test/models/post_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: @@ -292,9 +285,8 @@ 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_post_without_title(PostTest) [test/models/post_test.rb:6]: +Saved the post without a title ``` Now to get this test to pass we can add a model level validation for the _title_ field. @@ -308,13 +300,12 @@ end Now the test should pass. Let us verify by running the test again: ```bash -$ ruby -Itest test/unit/post_test.rb -n test_should_not_save_post_without_title -Loaded suite unit/post_test -Started +$ rails test test/models/post_test.rb -n test_should_not_save_post_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). @@ -334,18 +325,17 @@ end Now you can see even more output in the console from running the tests: ```bash -$ ruby -Itest test/unit/post_test.rb -n test_should_report_error -Loaded suite -e -Started +$ rails test test/models/post_test.rb -n 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' +NameError: undefined local variable or method `some_undefined_variable' for #<PostTest:0x007fe32e24afe0> + test/models/post_test.rb:10:in `block in <class:PostTest>' -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. @@ -511,6 +501,21 @@ You also have access to three instance variables in your functional tests: * `@request` - The request * `@response` - The response +### Setting Headers and CGI variables + +Headers and cgi variables can be set directly on the `@request` +instance variable: + +```ruby +# setting a HTTP Header +@request.headers["Accepts"] = "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` @@ -642,12 +647,9 @@ 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 ``` @@ -755,23 +757,28 @@ 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. +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. + +| Tasks | Description | +| ------------------------ | ----------- | +| `rails test` | Runs all unit, functional and integration tests. You can also simply run `rails test` as Rails will run all the tests by default| +| `rails test controllers` | Runs all the controller tests from `test/controllers`| +| `rails test functionals` | Runs all the functional tests from `test/controllers`, `test/mailers`, and `test/functional`| +| `rails test helpers` | Runs all the helper tests from `test/helpers`| +| `rails test integration` | Runs all the integration tests from `test/integration`| +| `rails test mailers` | Runs all the mailer tests from `test/mailers`| +| `rails test models` | Runs all the model tests from `test/models`| +| `rails test units` | Runs all the unit tests from `test/models`, `test/helpers`, and `test/unit`| -| 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: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: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`| +There're also some test commands which you can initiate by running rake tasks: +| 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:recent` | Tests recent changes| +| `rake test:uncommitted` | Runs all the tests which are uncommitted. Supports Subversion and Git| -Brief Note About `Test::Unit` +Brief Note About `MiniTest` ----------------------------- 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 @@ -920,19 +927,24 @@ 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 + assert !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: @@ -944,9 +956,17 @@ 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`). -This way, emails are not actually sent, simply constructed. The precise content of the email can then be checked against what is expected, as in the example above. +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 |