Test-Driven Development (TDD)

Introduction

Test-Driven Development (TDD) is a software development methodology in which developers write tests before writing the actual code. The process ensures that the code meets the desired requirements and remains robust throughout its lifecycle.

Benefits

Encourages writing modular, testable code.
Helps catch bugs early in the development process.
Improves confidence when making changes to the codebase.
Documents code behavior through tests.

The TDD Cycle

TDD follows a simple three-step process:

Red: Write a failing test for the desired functionality.
Green: Write the minimal code necessary to make the test pass.
Refactor: Improve the code structure while ensuring all tests still pass.

Example

Suppose you want to write a function to calculate the sum of two numbers. Using TDD, you would follow these steps:

Step 1: Write a Test

@Test
void testAddition() {
    Calculator calculator = new Calculator();
    assertEquals(5, calculator.add(2, 3));
}

Step 2: Write Minimal Code

class Calculator {
    int add(int a, int b) {
        return a + b;
    }
}

Step 3: Refactor

In this case, the code is already simple and requires no refactoring. For more complex scenarios, improve the design while keeping the tests green.

Takeaway

Test-Driven Development ensures that your code meets requirements, is reliable, and can adapt to changes. By writing tests first, you build a solid foundation for high-quality software.

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