Book Image

MOCKITO COOKBOOK

By : Grzejszczak
Book Image

MOCKITO COOKBOOK

By: Grzejszczak

Overview of this book

This is a focused guide with lots of practical recipes with presentations of business issues and presentation of the whole test of the system. This book shows the use of Mockito's popular unit testing frameworks such as JUnit, PowerMock, TestNG, and so on. If you are a software developer with no testing experience (especially with Mockito) and you want to start using Mockito in the most efficient way then this book is for you. This book assumes that you have a good knowledge level and understanding of Java-based unit testing frameworks.

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MOCKITO COOKBOOK
Grzejszczak
Jun, 2014 | 284 pages
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Table of Contents (12 chapters)
Preface
Preface
What this book covers
What you need for this book
Who this book is for
Conventions
Reader feedback
Customer support
Free Chapter
1
1. Getting Started with Mockito
1. Getting Started with Mockito
Introduction
Adding Mockito to a project's classpath
Getting started with Mockito for JUnit
Getting started with Mockito for TestNG
Mockito best practices – test behavior not implementation
Adding Mockito hints to exception messages (JUnit) (Experimental)
Adding additional Mockito warnings to your tests (JUnit) (Experimental)
2
2. Creating Mocks
2. Creating Mocks
Introduction
Creating mocks in code
Creating mocks with annotations
Creating mocks with a different default answer
Creating mocks with different default answers with annotations
Creating mocks with custom configuration
Creating mocks of final classes with PowerMock
Creating mocks of enums with PowerMock
3
3. Creating Spies and Partial Mocks
3. Creating Spies and Partial Mocks
Introduction
Creating spies in code
Creating spies with custom configuration
Creating spies using annotations
Creating partial mocks
Creating partial mocks of final classes with delegatesTo()
Creating spies of final classes with PowerMock
4
4. Stubbing Behavior of Mocks
4. Stubbing Behavior of Mocks
Introduction
Using argument matchers for stubbing
Stubbing methods that return values
Stubbing methods so that they throw exceptions
Stubbing methods so that they return custom answers
Stubbing methods so that they call real methods
Stubbing void methods
Stubbing void methods so that they throw exceptions
Stubbing void methods so that they return custom answers
Stubbing void methods so that they call real methods
Stubbing final methods with PowerMock
Stubbing static methods with PowerMock
Stubbing object instantiation using PowerMock
5
5. Stubbing Behavior of Spies
5. Stubbing Behavior of Spies
Introduction
Stubbing methods that return values
Stubbing methods so that they throw exceptions
Stubbing methods so that they return custom answers
Stubbing void methods
Stubbing void methods so that they throw exceptions
Stubbing void methods so that they return custom answers
Stubbing final methods with PowerMock
6
6. Verifying Test Doubles
6. Verifying Test Doubles
Introduction
Verifying the method invocation count with times()
Verifying the method invocation count with atLeast()
Verifying the method invocation count with atMost()
Verifying that interactions never happened
Verifying that interactions stopped happening
Verifying the order of interactions
Verifying interactions and ignoring stubbed methods
Verifying the method invocation within the specified time
7
7. Verifying Behavior with Object Matchers
7. Verifying Behavior with Object Matchers
Introduction
Using Hamcrest matchers for assertions
Creating custom Hamcrest matchers
Using Hamcrest matchers for stubbing and verification
Using AssertJ for assertions
Creating custom AssertJ assertions
Capturing and asserting the argument
8
8. Refactoring with Mockito
8. Refactoring with Mockito
Introduction
Removing the problems with instance creation
Refactoring classes that do too much
Refactoring the classes that use the class casts
Refactoring the classes that use static methods
Refactoring the tests that use too many mocks
9
9. Integration Testing with Mockito and DI Frameworks
9. Integration Testing with Mockito and DI Frameworks
Introduction
Injecting test doubles instead of beans using Spring's code configuration
Injecting test doubles instead of beans using Spring's XML configuration
Injecting test doubles instead of beans using Springockito
Injecting test doubles instead of beans with Guice
Injecting test doubles instead of beans with Guice using Jukito
10
10. Mocking Libraries Comparison
10. Mocking Libraries Comparison
Introduction
Mockito versus EasyMock
Mockito versus JMockit
Mockito versus JMock
Mockito versus Spock
11
Index
Index

Removing the problems with instance creation

In this recipe, we will first test an existing class that uses new to instantiate an object which performs complex logic; then, we'll refactor it. The problem with the new operator is that it's very difficult to mock the created instance. An object's collaborators should be passed as parameters of the constructor or somehow injected via the dependency injection system.

Getting ready

Let's assume that our system under test is a system that generates a new identity for a given person who can have a name, an age, and siblings. Note that the following snippet presents a poorly designed class:

public class BadlyDesignedNewPersonGenerator {

    public Person generateNewIdentity(Person person) {
        NewIdentityCreator newIdentityCreator = new NewIdentityCreator();
        String newName = newIdentityCreator.createNewName(person);
        int newAge = newIdentityCreator.createNewAge(person);
        List<Person> newSiblings = newIdentityCreator...
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