Fortunately, making our systems testable pushes us toward a design where our classes are small and single purpose. It’s just easier to test classes that conform to the SRP. The more tests we write, the more we’ll continue to push toward things that are simpler to test. So making sure our system is fully testable helps us create better designs. Tight coupling makes it difficult to write tests. So, similarly, the more tests we write, the more we use principles like DIP and tools like dependency injection, interfaces, and abstraction to minimize coupling. Our designs improve even more.
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