Exercises to practice breaking dependencies in legacy code to create tests for it.

We have some legacy code. We need to make changes. To make changes we need to introduce tests first. We might have to change some code to enable testing. We need to introduce so-called Seams (see Michael Feathers' Working Effectively with Legacy Code).

Changing code without test is risky, so we want to

• Only change as little code as possible.
• Rely on automated Refactoring tools as much as possible.
• You must not change the public API of the class.

• Parametrise Constructor
• Subclass And Override Method
• Extract And Override Call
• Replace Global Reference With Getter
• Extract And Override Factory Method

Planned

• Extract Interface
• Adapt Parameter

Each task presents you with a class and some collaborators.

• Bring this class under test. Make sure to cover all paths in the core logic.
• There is an existing test class with a first test case which might or might not work.
• You cannot change collaborators because they are used by other teams as well.

New BSD License, see license.txt in repository.

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