Behavior-Driven Development с RSpec и Cucumber

Behavior-Driven Developmentс RSpec и CucumberСтефан Кънев

http://skanev.com/

27.06.2009, TechCamp.eu

Tuesday, April 27, 2010

http://skanev.com

http://skanev.com

Автоматизирано тестване


Unit Tests

Test-Driven Development

Behavior-Driven Development


1. Unit test-ове

2. Test-Driven

3. Behavior-Driven

4. RSpec

5. Cucumber


class Programmer def implement_a_change(project, change) files = self.open_related_files(project, change) while true self.attempt_change(change, files) project.run() result = self.click_around_and_test(project) project.stop() break if result.successful? end self.commit_code(files) self.hope_everything_went_ok() endend


Repetitive...


...boring...


...error-prone


Машина, която да го прави вместо нас


Програма, която да го прави вместо нас


Unit Test


Пишем код, който проверява дали друг код

работи правилно.


С един бутон

Да Не


caladan:trane aquarius$ rake spec(in /work/trane)...............................................................................................................................................................................................................

Finished in 8.334414 seconds

207 examples, 0 failures


caladan:trane aquarius$ rake spec(in /work/trane).....................................................................................................................................................................................................F.........

1)'User should know something' FAILEDexpected: "something", got: "nothing" (using ==)./spec/models/user_spec.rb:32:

Finished in 8.123368 seconds

207 examples, 1 failure


I can has value?


Време


Regression testing


Документация(развален английски + стари версии = fun)


Спецификация


1. Unit test-ове

2. Test-Driven

3. Behavior-Driven

4. RSpec

5. Cucumber


Unit test-овете са просто инструмент


Test-Driven Development е подход към писането на софтуер


test-first


red/green/refactor


red/green/refactor

Възможно най-простия тест, който проверява функцио-налността и не минава.


red/green/refactor

Най-простата имплементация, която кара тестът да минава успешно.


red/green/refactor

Отстраняване на повторения, докато кодът не стане достатъчно качествен.


малки стъпки


Test-Driven Design


Преизползваемост


Low coupling


Добър интерфейс


scope creep


up-front design


1. Unit test-ове

2. Test-Driven

3. Behavior-Driven

4. RSpec

5. Cucumber


Test-Driven Development is not about testing


TDD ≠ QA


Опитните TDD-ри използват процеса за да открият поведението, което системата трябва

да има.


Behavior-Driven Development


BDD ≈ TDD++


"Getting the words right"


Test-Driven ⇒ Behavior-Driven


Assertion ⇒ Expectation


Test Method ⇒Code Example


Test Case ⇒ Example Group


Domain-Driven Design


Eric Evans

Domain Driven Design


Близки до проблемната област думи


Разбираем за бизнеса език


BDD = TDD + DDD(TLA FTW)


BDD = TDD + DDD


BDD = TDD + DDD

BDD = (T + D)DD


BDD = TDD + DDD

BDD = (T + D)DD

B = T + D


BDD = TDD + DDD

BDD = (T + D)DD

B = T + D

интензитет = време + доза


1. Unit test-ове

2. Test-Driven

3. Behavior-Driven

4. RSpec

5. Cucumber


Друг "синтаксис"


xUnit assert_equal 42, answer




RSpec answer.should equal(42)




RSpec answer.should equal(42)

English Answer should equal 42



assert_equal 42, result


assert_equal 42, result result.should == 42


assert_equal 42, result result.should == 42assert result.nil?


assert_equal 42, result result.should == 42assert result.nil? result.should be_nil


assert_equal 42, result result.should == 42assert result.nil? result.should be_nilassert result.kind_of?(User)


assert_equal 42, result result.should == 42assert result.nil? result.should be_nilassert result.kind_of?(User) result.should be_kind_of(User)


assert_equal 42, result result.should == 42assert result.nil? result.should be_nilassert result.kind_of?(User) result.should be_kind_of(User)assert [], blog.posts


assert_equal 42, result result.should == 42assert result.nil? result.should be_nilassert result.kind_of?(User) result.should be_kind_of(User)assert [], blog.posts blog.should have(:no).posts


assert_equal 42, result result.should == 42assert result.nil? result.should be_nilassert result.kind_of?(User) result.should be_kind_of(User)assert [], blog.posts blog.should have(:no).postsassert 5, blog.posts.size


assert_equal 42, result result.should == 42assert result.nil? result.should be_nilassert result.kind_of?(User) result.should be_kind_of(User)assert [], blog.posts blog.should have(:no).postsassert 5, blog.posts.size blog.should have(5).posts


assert_raise(InvalidRecord) do user.save!end



lambda { user.save! }.should raise_error(InvalidRecord)




assert_difference "User.count", 1 do user.create!end




assert_difference "User.count", 1 do user.create!end

lambda { user.save! }.should change { User.count }.by(1)


class Stack < Test::Unit::TestCase def set_up() @stack = Stack.new end def test_empty assert @stack.empty? @stack.push 42 assert [email protected]? end def test_pop @stack.push 42 @stack.push 5 assert_equal 5, @stack.pop assert_equal 42, @stack.pop asser_raise(StackEmptyError) { @stack.pop } endend


describe Stack do before(:each) do @stack = Stack.new end it "should be able to tell whether it is empty" do @stack.should be_empty @stack.push 42 @stack.should_not be_empty? end it "should pop the items in reverse order" do @stack.push 42 @stack.push 5 @stack.pop.should == 5 @stack.pop.should == 42 lambda { @stack.pop }.should raise_error(StackEmptyError) endend


describe Stack do context "(empty stack)" do it "should be empty" it "#pop should raise an exception" end context "(non-empty stack)" do it "should not be empty" it "#pop should return the top element" it "#pop should remove the top element" endend


1. Unit test-ове

2. Test-Driven

3. Behavior-Driven

4. RSpec

5. Cucumber


Feature: Manage posts In order to be able to spread wisdom the blogger wants to be able to write about anything he wants Scenario: Writing a new post Given that there are no posts And I am logged in When I go to the new post page And I fill "Title" with "F1rst p0st" And I fill "Content" with "This is my first post" And I press "Publish" Then I should be on the front page And I should see "This is my first post" And there should be a new post called "F1rst p0st"


Behavior-Driven Development с RSpec и Cucumber

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