testing legacy rails apps

Evan ‘rabble’ Henshaw-Plath Yahoo! Brickhouse

anarchogeek.com - testingrails.compresentation slides - slideshare.net/rabble

Testing LegacyRails Applications

Yes, thousands of rails apps have been built and deployed over the last three years. Many of us included few or no tests. The test-less apps still need debugging, which should be done with tests.

Do We HaveLegacy Already?

Yes, thousands of rails apps have been built and deployed over the last three years. Many of us included few or no tests. The test-less apps still need debugging, which should be done with tests.

Testing == Health Food?

“We started the tests, but haven’t been updating them”

“Who has time for tests?”

“Testing means writing twice as much code.”

Testing == Debugging

no, really, it is

Starting

Don’t do it all at once

Get Rake Working

brickhouse:~/code/legacy_testing rabble$ rake(in /Users/rabble/code/legacy_testing)/opt/local/bin/ruby -Ilib:test "/opt/local/lib/ruby/gems/1.8/gems/rake-0.7.2/lib/rake/rake_test_loader.rb" /opt/local/bin/ruby -Ilib:test "/opt/local/lib/ruby/gems/1.8/gems/rake-0.7.2/lib/rake/rake_test_loader.rb" #42000Unknown database 'legacy_testing_development'/opt/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/vendor/mysql.rb:523:in `read'/opt/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/vendor/mysql.rb:153:in `real_connect'/opt/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/connection_adapters/mysql_adapter.rb:389:in `connect'/opt/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/connection_adapters/mysql_adapter.rb:152:in `initialize'

Create your test db

mysqladmin -uroot create railsapp_test

Use Migrations

brickhouse:~/code/legacy_testing rabble$ rake db:migrate (in /Users/rabble/code/legacy_testing)== CreateArticles: migrating ====================-- create_table(:articles) -> 0.2749s== CreateArticles: migrated (0.2764s) =============

Try Rake Again

brickhouse:~/code/legacy_testing rabble$ rake(in /Users/rabble/code/legacy_testing)/opt/local/bin/ruby -Ilib:test "/opt/local/lib/ruby/gems/1.8/gems/rake-0.7.2/lib/rake/rake_test_loader.rb" "test/unit/article_test.rb" Loaded suite /opt/local/lib/ruby/gems/1.8/gems/rake-0.7.2/lib/rake/rake_test_loaderStarted.Finished in 0.316844 seconds.

1 tests, 1 assertions, 0 failures, 0 errors/opt/local/bin/ruby -Ilib:test "/opt/local/lib/ruby/gems/1.8/gems/rake-0.7.2/lib/rake/rake_test_loader.rb" "test/functional/blog_controller_test.rb" Loaded suite /opt/local/lib/ruby/gems/1.8/gems/rake-0.7.2/lib/rake/rake_test_loaderStarted.Finished in 0.243161 seconds.

1 tests, 1 assertions, 0 failures, 0 errors/opt/local/bin/ruby -Ilib:test "/opt/local/lib/ruby/gems/1.8/gems/rake-0.7.2/lib/rake/rake_test_loader.rb"

Scaffolding is Broken

Ok nowwe’rereadyto getstarted

One Step At A TimeOne Step At A Time

find a bug - write a test

refractor a methodwrite a test

Treat EachMethod As Box

Test One Thing

At A Time

What Goes In?

What Comes Out?

Running Tests

rake & directly

Running Testswith rake

rake test # Test all units and functionalsrake test:functionals # Run the functional tests in test/functionalrake test:integration # Run the integration tests in test/integrationrake test:plugins # Run the plugin tests in vendor/plugins/**/testrake test:recent # Test recent changesrake test:uncommitted # Test changes since last checkin (svn only)rake test:units # Run the unit tests in test/unit

running tests directlyTest::Unit automatic runner.Usage: blog_controller_test.rb [options] [-- untouched arguments]

run them allruby article_controller_test.rb

give it a test nameruby article_controller_test.rb -n test_show

try regular expressionsruby article_controller_test.rb -n /show/

get help: ruby --help

An Example def User.find_popular(n=20) sql = "select u.*, count(j.user_id) as popularity from users u, talks_users j where u.id = j.user_id group by j.user_id order by popularity desc limit #{n}" return User.find_by_sql(sql) end

An Example def User.find_popular(n=20) sql = "select u.*, count(j.user_id) as popularity from users u, talks_users j where u.id = j.user_id group by j.user_id order by popularity desc limit #{n}" return User.find_by_sql(sql) end

def test_popular assert_nothing_raised { users = User.find_popular(2) } assert_equal 2, users.size, "find_popular should return two users" assert users.first.popularity > users.last.popularity, "should sort popular users" end

$ ruby ./test/unit/user_test -n test_popularbrickhouse:~/code/icalico/trunk/test/unit rabble$ ruby user_test.rb -n /popular/Loaded suite user_testStarted.Finished in 0.290563 seconds.

Refactor def self.find_popular(n=20) return conference.attendees.find(:all, :select => "users.*, count(talks_users.user_id) as popularity", :joins => "LEFT JOIN talks_users on users.id = talks_users.user_id", :group => "talks_users.user_id", :order => 'popularity', :limit => n )end

$ ruby ./test/unit/user_test -n test_popularbrickhouse:~/code/icalico/trunk/test/unit rabble$ ruby user_test.rb -n /popular/Loaded suite user_testStartedFFinished in 0.290563 seconds.

1) Failure:test_popular(UserTest) [user_test.rb:10]:Exception raised:Class: <NoMethodError>Message: <"You have a nil object when you didn't expect it!\nThe error occured while evaluating nil.attendees">---Backtrace---/Users/rabble/code/icalico/trunk/config/../app/models/user.rb:35:in `find_popular'user_test.rb:10:in `test_popular'user_test.rb:10:in `test_popular'---------------

Refactor def self.find_popular(n=20) return self.find(:all, :select => "users.*, count(talks_users.user_id) as popularity", :conditions => ["users.conference_id = ? ", conference.id], :joins => "LEFT JOIN talks_users on users.id = talks_users.user_id", :group => "talks_users.user_id", :order => 'popularity', :limit => n )end

$ ruby ./test/unit/user_test -n test_popularbrickhouse:~/code/icalico/trunk/test/unit rabble$ ruby user_test.rb -n /popular/Loaded suite user_testStarted.Finished in 0.290563 seconds.

build test from logs

Processing ArticlesController#show (for 0.0.0.0 at 2006-07-20 11:28:23) [GET] Session ID: Parameters: {"action"=>"show", "id"=>"2", "controller"=>"articles"} Article Load (0.002371) SELECT * FROM articles LIMIT 1Rendering within layouts/articlesRendering articles/show Article Columns (0.007194) SHOW FIELDS FROM articlesCompleted in 0.10423 (9 reqs/sec) | Rendering: 0.08501 (81%) | DB: 0.01022 (9%) | 200 OK [http://test.host/articles/show/1]

./log/development.log

the functional test

require File.dirname(__FILE__) + '/../test_helper'require 'articles_controller'

# Re-raise errors caught by the controller.class ArticlesController def rescue_action(e) raise e endend

class ArticlesControllerTest &lt; Test::Unit::TestCase def setup @controller = ArticlesController.new @request = ActionController::TestRequest.new @response = ActionController::TestResponse.new end

# Replace this with your real tests. def test_truth assert true endend

./test/functional/article_controller_test.rb

get the params

Processing ArticlesController#show (for 0.0.0.0 at 2006-07-20 11:28:23) [GET] Session ID: Parameters: {"action"=>"show", "id"=>"2", "controller"=>"articles"} Article Load (0.002371) SELECT * FROM articles LIMIT 1Rendering within layouts/articlesRendering articles/show Article Columns (0.007194) SHOW FIELDS FROM articlesCompleted in 0.10423 (9 reqs/sec) | Rendering: 0.08501 (81%) | DB: 0.01022 (9%) | 200 OK [http://test.host/articles/show/1]

./log/development.log

what to test?

1. Assert that the page action rendered and returned successful HTTP response code, i.e. 200.

2. Assert that the correct template was rendered.

3. Assert that action assigns a value to the @article variable.

4. Assert that the right @article object was loaded.

writing the test

def test_show get :show, {"action"=>"show", "id"=>"2", "controller"=>"articles"}

#confirm that the http response was a 200 (i.e. success) assert_response :success

#confirm that the correct template was used for this action assert_template 'articles/show'

#confirm that the variable @article was assigned a value assert assigns( :article )

#confirm that the @article object loaded has the id we want assert_equal 2, assigns( :article ).idend

./test/functional/article_controller_test.rb

running the test

rabble:~/code/tblog/test/functional evan$ ruby \articles_controller_test.rb -n test_show Loaded suite articles_controller_test Started F Finished in 0.625045 seconds.

1) Failure: test_show(ArticlesControllerTest) [articles_controller_test.rb:27]: <2> expected but was <1>.

1 tests, 4 assertions, 1 failures, 0 errors

fix the bug

The old codeapp/controller/articles_controller.rb:

def show @article = Article.find(:first) end

The fix is easy, we update it so the Article.find method

app/controller/articles_controller.rb:

def show @article = Article.find(params[:id]) end

running the test

rabble:~/code/tblog/test/functional evan$ ruby \articles_controller_test.rb -n test_showLoaded suite articles_controller_testStarted .Finished in 0.426828 seconds.

1 tests, 3 assertions, 0 failures, 0 errors

test coverage

rake stats

brickhouse:~/code/icalico/trunk rabble$ rake stats(in /Users/rabble/code/icalico/trunk)+----------------------+-------+-------+---------+---------+-----+-------+| Name | Lines | LOC | Classes | Methods | M/C | LOC/M |+----------------------+-------+-------+---------+---------+-----+-------+| Helpers | 107 | 81 | 0 | 9 | 0 | 7 || Controllers | 517 | 390 | 10 | 52 | 5 | 5 || Components | 0 | 0 | 0 | 0 | 0 | 0 || Functional tests | 416 | 299 | 18 | 58 | 3 | 3 || Models | 344 | 250 | 8 | 37 | 4 | 4 || Unit tests | 217 | 159 | 9 | 25 | 2 | 4 || Libraries | 257 | 162 | 4 | 32 | 8 | 3 || Integration tests | 0 | 0 | 0 | 0 | 0 | 0 |+----------------------+-------+-------+---------+---------+-----+-------+| Total | 1858 | 1341 | 49 | 213 | 4 | 4 |+----------------------+-------+-------+---------+---------+-----+-------+ Code LOC: 883 Test LOC: 458 Code to Test Ratio: 1:0.5

rcov test coverage

rcov test coverage

what needs to be tested?

rcov test coverage

what gets executed when you run tests

rcov test coveragesummary

rcov test coverageper file reports

Heckle

more lateron this

autotest

because sometimes our tests can run themselves

autotest

Continuous Integration

You can go deeperYou can go deeper

FixturesUgliness

ar_fixturesuse mocksfixture senarios

zentest

focus on the bugs

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Next: Heckle

Evan ‘rabble’ Henshaw-Plath Yahoo! Brickhouseanarchogeek.com testingrails.comslides: slideshare.net/rabble

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