How do you plan and implement testing within a project?

To plan testing in a C# project, I usually start by defining requirements and key use cases. Then I break down functionality into modules and create a list of test cases covering both positive and negative scenarios.

Implementing testing includes:

• Writing unit tests using frameworks like NUnit or xUnit.
• Using mocks and stubs to isolate components (e.g., with Moq).
• Automating test runs through CI/CD for timely verification with each commit.
• Adding integration and UI tests if necessary.

An example of a simple unit test with NUnit:

[Test]
public void Add_TwoNumbers_ReturnsSum()
{
    var calculator = new Calculator();
    var result = calculator.Add(2, 3);
    Assert.AreEqual(5, result);
}

This approach helps quickly identify errors and maintain code quality throughout the development cycle.