book

Unit Testing Principles, Practices, and Patterns

by Vladimir Khorikov

January 2020

Intermediate to advanced

304 pages

9h 8m

English

Manning Publications

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1.1. The current state of unit testing1.2. The goal of unit testing1.3. Using coverage metrics to measure test suite quality1.4. What makes a successful test suite?1.5. What you will learn in this bookSummary

2.1. The definition of “unit test”2.2. The classical and London schools of unit testing2.3. Contrasting the classical and London schools of unit testing2.4. Integration tests in the two schoolsSummary
3.1. How to structure a unit test3.2. Exploring the xUnit testing framework3.3. Reusing test fixtures between tests3.4. Naming a unit test3.5. Refactoring to parameterized tests3.6. Using an assertion library to further improve test readabilitySummary
4.1. Diving into the four pillars of a good unit test4.2. The intrinsic connection between the first two attributes4.3. The third and fourth pillars: Fast feedback and maintainability4.4. In search of an ideal test4.5. Exploring well-known test automation conceptsSummary
5.1. Differentiating mocks from stubs5.2. Observable behavior vs. implementation details5.3. The relationship between mocks and test fragility5.4. The classical vs. London schools of unit testing, revisitedSummary
6.1. The three styles of unit testing6.2. Comparing the three styles of unit testing6.3. Understanding functional architecture6.4. Transitioning to functional architecture and output-based testing6.5. Understanding the drawbacks of functional architectureSummary
7.1. Identifying the code to refactor7.2. Refactoring toward valuable unit tests7.3. Analysis of optimal unit test coverage7.4. Handling conditional logic in controllers7.5. ConclusionSummary
8.1. What is an integration test?8.2. Which out-of-process dependencies to test directly8.3. Integration testing: An example8.4. Using interfaces to abstract dependencies8.5. Integration testing best practices8.6. How to test logging functionality8.7. ConclusionSummary
9.1. Maximizing mocks’ value9.2. Mocking best practicesSummary
10.1. Prerequisites for testing the database10.2. Database transaction management10.3. Test data life cycle10.4. Reusing code in test sections10.5. Common database testing questions10.6. ConclusionSummary
11.1. Unit testing private methods11.2. Exposing private state11.3. Leaking domain knowledge to tests11.4. Code pollution11.5. Mocking concrete classes11.6. Working with time11.7. ConclusionSummary

Content preview from Unit Testing Principles, Practices, and Patterns

Chapter 5. Mocks and test fragility

This chapter covers

Differentiating mocks from stubs
Defining observable behavior and implementation details
Understanding the relationship between mocks and test fragility
Using mocks without compromising resistance to refactoring

Chapter 4 introduced a frame of reference that you can use to analyze specific tests and unit testing approaches. In this chapter, you’ll see that frame of reference in action; we’ll use it to dissect the topic of mocks.

The use of mocks in tests is a controversial subject. Some people argue that mocks are a great tool and apply them in most of their tests. Others claim that mocks lead to test fragility and try not to use them at all. As the saying goes, the truth lies somewhere ...