JUnit in Action, Third Edition

JUnit is the gold standard for unit testing Java applications. Filled with powerful new features designed to automate software testing, JUnit 5 boosts your productivity and helps avoid debugging nightmares. Whether you're just starting with JUnit or you want to ramp up on the new features, JUnit in Action, Third Edition has you covered. Extensively revised with new code and new chapters, JUnit in Action, Third Edition is an up-to-date guide to smooth software testing. Dozens of hands-on examples illustrate JUnit 5's innovations for dependency injection, nested testing, parameterized tests, and more. Throughout, you’ll learn how to use JUnit 5 to automate your testing, for a process that consumes less resources, and gives you more time for developing. About the Technology The JUnit framework is the gold standard for unit testing Java applications—and knowing it is an essential skill for Java developers. The latest version, JUnit 5, is a total overhaul, now supporting modern Java features like Lambdas and Streams. About the book JUnit in Action, Third Edition has been completely rewritten for this release. The book is full of examples that demonstrate JUnit's modern features, including its new architecture; nested, tagged, and dynamic tests; and dependency injection. You'll benefit from author Cătălin Tudose's unique "pyramid" testing strategy, which breaks the testing process into layers and sets you on the path to bug-free code creation. What's inside • Migrating from JUnit 4 to 5 • Effective test automation • Test-driven development and behavior-driven development • Using mocks for test isolation • Connecting JUnit 5 with Maven or Gradle About the reader For intermediate Java developers. About the authors Cătălin Tudose has a Ph.D. in Computer Science, and over 15 years of experience as a Senior Java Developer and Technical Team Lead. Previous editions were authored by Petar Tahchiev, Felipe Leme, Gary Gregory, and Vincent Massol. JUnit in Action contents preface acknowledgments about this book Who should read this book How this book is organized: A roadmap About the code liveBook discussion forum about the author about the cover illustration Part 1 JUnit 1 JUnit jump-start 1.1 Proving that a program works 1.2 Starting from scratch 1.2.1 Understanding unit testing frameworks 1.2.2 Adding unit tests 1.3 Setting up JUnit 1.4 Testing with JUnit Summary 2 Exploring core JUnit 2.1 Core annotations 2.1.1 The @DisplayName annotation 2.1.2 The @Disabled annotation 2.2 Nested tests 2.3 Tagged tests 2.4 Assertions 2.5 Assumptions 2.6 Dependency injection in JUnit 5 2.6.1 TestInfoParameterResolver 2.6.2 TestReporterParameterResolver 2.6.3 RepetitionInfoParameterResolver 2.7 Repeated tests 2.8 Parameterized tests 2.9 Dynamic tests 2.10 Using Hamcrest matchers Summary 3 JUnit architecture 3.1 The concept and importance of software architecture 3.1.1 Story 1: The telephone directories 3.1.2 Story 2: The sneakers manufacturer 3.2 The JUnit 4 architecture 3.2.1 JUnit 4 modularity 3.2.2 JUnit 4 runners 3.2.3 JUnit 4 rules 3.2.4 Shortcomings of the JUnit 4 architecture 3.3 The JUnit 5 architecture 3.3.1 JUnit 5 modularity 3.3.2 JUnit Platform 3.3.3 JUnit Jupiter 3.3.4 JUnit Vintage 3.3.5 The big picture of the JUnit 5 architecture Summary 4 Migrating from JUnit 4 to JUnit 5 4.1 Migration steps between JUnit 4 and JUnit 5 4.2 Needed dependencies 4.3 Annotations, classes, and methods 4.3.1 Equivalent annotations, classes, and methods 4.3.2 Categories vs. tags 4.3.3 Migrating Hamcrest matcher functionality 4.3.4 Rules vs. the extension model 4.3.5 Custom rules Summary 5 Software testing principles 5.1 The need for unit tests 5.1.1 Allowing greater test coverage 5.1.2 Increasing team productivity 5.1.3 Detecting regressions and limiting debugging 5.1.4 Refactoring with confidence 5.1.5 Improving implementation 5.1.6 Documenting expected behavior 5.1.7 Enabling code coverage and other metrics 5.2 Test types 5.2.1 Unit testing 5.2.2 Integration software testing 5.2.3 System software testing 5.2.4 Acceptance software testing 5.3 Black-box vs. white-box testing 5.3.1 Black-box testing 5.3.2 White-box testing 5.3.3 Pros and cons Summary Part 2 Different testing strategies 6 Test quality 6.1 Measuring test coverage 6.1.1 Introduction to test coverage 6.1.2 Tools for measuring code coverage 6.2 Writing testable code 6.2.1 Understanding that public APIs are contracts 6.2.2 Reducing dependencies 6.2.3 Creating simple constructors 6.2.4 Following the Law of Demeter (Principle of Least Knowledge) 6.2.5 Avoiding hidden dependencies and global state 6.2.6 Favoring generic methods 6.2.7 Favoring composition over inheritance 6.2.8 Favoring polymorphism over conditionals 6.3 Test-driven development 6.3.1 Adapting the development cycle 6.3.2 Doing the TDD two-step 6.4 Behavior-driven development 6.5 Mutation testing 6.6 Testing in the development cycle Summary 7 Coarse-grained testing with stubs 7.1 Introducing stubs 7.2 Stubbing an HTTP connection 7.2.1 Choosing a stubbing solution 7.2.2 Using Jetty as an embedded server 7.3 Stubbing the web server resources 7.3.1 Setting up the first stub test 7.3.2 Reviewing the first stub test 7.4 Stubbing the connection 7.4.1 Producing a custom URL protocol handler 7.4.2 Creating a JDK HttpURLConnection stub 7.4.3 Running the test Summary 8 Testing with mock objects 8.1 Introducing mock objects 8.2 Unit testing with mock objects 8.3 Refactoring with mock objects 8.3.1 Refactoring example 8.3.2 Refactoring considerations 8.4 Mocking an HTTP connection 8.4.1 Defining the mock objects 8.4.2 Testing a sample method 8.4.3 Try #1: Easy refactoring technique 8.4.4 Try #2: Refactoring by using a class factory 8.5 Using mocks as Trojan horses 8.6 Introducing mock frameworks 8.6.1 Using EasyMock 8.6.2 Using JMock 8.6.3 Using Mockito Summary 9 In-container testing 9.1 Limitations of standard unit testing 9.2 The mock-objects solution 9.3 The step to in-container testing 9.3.1 Implementation strategies 9.3.2 In-container testing frameworks 9.4 Comparing stubs, mock objects, and in-container testing 9.4.1 Stubs evaluation 9.4.2 Mock-objects evaluation 9.4.3 In-container testing evaluation 9.5 Testing with Arquillian Summary Part 3 Working with JUnit 5 and other tools 10 Running JUnit tests from Maven 3 10.1 Setting up a Maven project 10.2 Using the Maven plugins 10.2.1 Maven compiler plugin 10.2.2 Maven Surefire plugin 10.2.3 Generating HTML JUnit reports with Maven 10.3 Putting it all together 10.4 Maven challenges Summary 11 Running JUnit tests from Gradle 6 11.1 Introducing Gradle 11.2 Setting up a Gradle project 11.3 Using Gradle plugins 11.4 Creating a Gradle project from scratch and testing it with JUnit 5 11.5 Comparing Gradle and Maven Summary 12 JUnit 5 IDE support 12.1 Using JUnit 5 with IntelliJ IDEA 12.2 Using JUnit 5 with Eclipse 12.3 Using JUnit 5 with NetBeans 12.4 Comparing JUnit 5 usage in IntelliJ, Eclipse, and NetBeans Summary 13 Continuous integration with JUnit 5 13.1 Continuous integration testing 13.2 Introducing Jenkins 13.3 Practicing CI on a team 13.4 Configuring Jenkins 13.5 Working on tasks in a CI environment Summary Part 4 Working with modern frameworks and JUnit 5 14 JUnit 5 extension model 14.1 Introducing the JUnit 5 extension model 14.2 Creating a JUnit 5 extension 14.3 Writing JUnit 5 tests using the available extension points 14.3.1 Persisting passengers to a database 14.3.2 Checking the uniqueness of passengers Summary 15 Presentation-layer testing 15.1 Choosing a testing framework 15.2 Introducing HtmlUnit 15.2.1 A live example 15.3 Writing HtmlUnit tests 15.3.1 HTML assertions 15.3.2 Testing for a specific web browser 15.3.3 Testing more than one web browser 15.3.4 Creating standalone tests 15.3.5 Testing forms 15.3.6 Testing JavaScript 15.4 Introducing Selenium 15.5 Writing Selenium tests 15.5.1 Testing for a specific web browser 15.5.2 Testing navigation using a web browser 15.5.3 Testing more than one web browser 15.5.4 Testing Google search and navigation using different web browsers 15.5.5 Testing website authentication 15.6 HtmlUnit vs. Selenium Summary 16 Testing Spring applications 16.1 Introducing the Spring Framework 16.2 Introducing dependency injection 16.3 Using and testing a Spring application 16.3.1 Creating the Spring context programmatically 16.3.2 Using the Spring TestContext framework 16.4 Using SpringExtension for JUnit Jupiter 16.5 Adding a new feature and testing it with JUnit 5 Summary 17 Testing Spring Boot applications 17.1 Introducing Spring Boot 17.2 Creating a project with Spring Initializr 17.3 Moving the Spring application to Spring Boot 17.4 Implementing a test-specific configuration for Spring Boot 17.5 Adding and testing a new feature in the Spring Boot application Summary 18 Testing a REST API 18.1 Introducing REST applications 18.2 Creating a RESTful API to manage one entity 18.3 Creating a RESTful API to manage two related entities 18.4 Testing the RESTful API Summary 19 Testing database applications 19.1 The database unit testing impedance mismatch 19.1.1 Unit tests must exercise code in isolation 19.1.2 Unit tests must be easy to write and run 19.1.3 Unit tests must be fast to run 19.2 Testing a JDBC application 19.3 Testing a Spring JDBC application 19.4 Testing a Hibernate application 19.5 Testing a Spring Hibernate application 19.6 Comparing the approaches for testing database applications Summary Part 5 Developing applications with JUnit 5 20 Test-driven development with JUnit 5 20.1 TDD main concepts 20.2 The flight-management application 20.3 Preparing the flight-management application for TDD 20.4 Refactoring the flight-management application 20.5 Introducing new features using TDD 20.5.1 Adding a premium flight 20.5.2 Adding a passenger only once Summary 21 Behavior-driven development with JUnit 5 21.1 Introducing behavior-driven development 21.1.1 Introducing a new feature 21.1.2 From requirements analysis to acceptance criteria 21.1.3 BDD benefits and challenges 21.2 Working BDD style with Cucumber and JUnit 5 21.2.1 Introducing Cucumber 21.2.2 Moving a TDD feature to Cucumber 21.2.3 Adding a new feature with the help of Cucumber 21.3 Working BDD style with JBehave and JUnit 5 21.3.1 Introducing JBehave 21.3.2 Moving a TDD feature to JBehave 21.3.3 Adding a new feature with the help of JBehave 21.4 Comparing Cucumber and JBehave Summary 22 Implementing a test pyramid strategy with JUnit 5 22.1 Software testing levels 22.2 Unit testing: Basic components working in isolation 22.3 Integration testing: Units combined into a group 22.4 System testing: Looking at the complete software 22.4.1 Testing with a mock external dependency 22.4.2 Testing with a partially implemented external dependency 22.4.3 Testing with the fully implemented external dependency 22.5 Acceptance testing: Compliance with business requirements Summary appendix A Maven A.1 Convention over configuration A.2 Strong dependency management A.3 Maven build life cycles A.4 Plugin-based architecture A.5 The Maven project object model (POM) A.6 Installing Maven appendix B Gradle B.1 Installing Gradle B.2 Creating Gradle tasks appendix C IDEs C.1 Installing IntelliJ IDEA C.2 Installing Eclipse C.3 Installing NetBeans appendix D Jenkins index Symbols A B C D E F G H I J K L M N O P Q R S T U V W X JUnit in Action - back JUnit in Action, Third Edition has been completely rewritten for this release. The book is full of examples that demonstrate JUnit's modern features, including its new architecture; nested, tagged, and dynamic tests; and dependency injection. Summary JUnit is the gold standard for unit testing Java applications. Filled with powerful new features designed to automate software testing, JUnit 5 boosts your productivity and helps avoid debugging nightmares. Whether you're just starting with JUnit or you want to ramp up on the new features, JUnit in Action, Third Edition has you covered. Extensively revised with new code and new chapters, JUnit in Action, Third Edition is an up-to-date guide to smooth software testing. Dozens of hands-on examples illustrate JUnit 5's innovations for dependency injection, nested testing, parameterized tests, and more. Throughout, youll learn how to use JUnit 5 to automate your testing, for a process that consumes less resources, and gives you more time for developing. Purchase of the print book includes a free eBook in PDF, Kindle, and ePub formats from Manning Publications. About the technology The JUnit framework is the gold standard for unit testing Java applicationsand knowing it is an essential skill for Java developers. The latest version, JUnit 5, is a total overhaul, now supporting modern Java features like Lambdas and Streams. About the book JUnit in Action, Third Edition has been completely rewritten for this release. The book is full of examples that demonstrate JUnit's modern features, including its new architecture; nested, tagged, and dynamic tests; and dependency injection. You'll benefit from author Catalin Tudose's unique "pyramid" testing strategy, which breaks the testing process into layers and sets you on the path to bug-free code creation. What's inside Migrating from JUnit 4 to 5 Effective test automation Test-driven development and behavior-driven development Using mocks for test isolation Connecting JUnit 5 with Maven or Gradle About the reader For intermediate Java developers. About the author Catalin Tudose has a Ph.D. in Computer Science, and over 15 years of experience as a Senior Java Developer and Technical Team Lead. Previous editions were authored by Petar Tahchiev, Felipe Leme, Gary Gregory, and Vincent Massol. Table of Contents PART 1 - JUNIT 1 JUnit jump-start 2 Exploring core JUnit 3 JUnit architecture 4 Migrating from JUnit 4 to JUnit 5 5 Software testing principles PART 2 - DIFFERENT TESTING STRATEGIES 6 Test quality 7 Coarse-grained testing with stubs 8 Testing with mock objects 9 In-container testing PART 3 - WORKING WITH JUNIT 5 AND OTHER TOOLS 10 Runing JUnit tests from Maven 3 11 Running JUnit tests from Gradle 6 12 JUnit 5 IDE support 13 Coninuous integration with JUnit 5 PART 4 - WORKING WITH MODERN FRAMEWORKS AND JUNIT 5 14 JUnit 5 extension model 15 Presentation-layer testing 16 Testing Spring applications 17 Testing Spring Boot applications 18 Testing a REST API 19 Testing database applications PART 5 - DEVELOPING APPLICATIONS WITH JUNIT 5 20 Test-driven development with JUnit 5 21 Behavior-driven development in JUnit 5 22 Implementing a test pyramid strategy with JUnit 5 The JUnit framework is the gold standard for unit testing Java applications, and knowing it is an essential skill for Java developers. The latest version, JUnit 5, is a total overhaul, now supporting modern Java features like Lambdas and Streams. JUnit in action, third edition has been completely rewritten for this release. The book is full of examples that demonstrate JUnit's modern features, including its new architecture; nested, tagged, and dynamic tests; and dependency injection. You'll benefit from author Cătălin Tudose's unique "pyramid" testing strategy, which breaks the testing process into layers and sets you on the path to bug-free code creation