PHP: Testing Legacy Applications

Learn how to write tests for legacy PHP code bases. Discover why legacy code can be tough to test, how to determine what to test, and how to plan and build testing scenarios.

Introduction

• Welcome
• What you need you to know
• Exercise files

1. What Changes When Testing Legacy Code

• TDD vs. test after
• How the tools change
• Quick primer on test doubles
• Code coverage and confidence levels
• Difficult people

2. Why Legacy Code Can Be Hard to Test

• Bootstrap sequences, part 1
• Bootstrap sequences, part 2
• Hard-coded dependencies
• Difficult deployments
• Poor package management practices

3. Laying the Foundation

• Just how many tests do we need?
• Tests as questions
• How we decide what to test?
• Real vs. monkey patch vs. double

4. Testing Legacy Code

• Why test a legacy application?
• Identifying dependencies
• Planning a scenario
• Building a scenario
• Planning real to doubles
• Building real to doubles
• Refactor your tests
• Add getters and setters

Conclusion

• Next steps