Test-Driven Development (TDD)

Test-Driven Development (TDD) is a software development approach where tests are written before the actual code. It follows a cycle of writing a failing test, writing the code to make the test pass, and then refactoring the code.

In TDD, developers start by writing a test that defines the desired behavior of the code. This test is written in such a way that it initially fails. Then, developers write the minimum amount of code necessary to pass the test. Once the test passes, the code is refactored to improve its design and maintainability without changing the behavior.

TDD has several benefits:

• Improved Code Quality: Writing tests first helps developers think about the design and behavior of the code before implementation. This can lead to more reliable and maintainable code.
• Rapid Feedback: TDD provides immediate feedback on the quality of the code. If a new feature breaks existing functionality, the tests will catch it early.
• Regression Testing: With TDD, a suite of tests is built up over time. These tests can be run frequently to ensure that previously developed and tested features still work as expected.

Here's an example of using TDD to develop a simple calculator in Python:

1# calculator.py
2
3def add_numbers(a, b):
4    return a + b
5
6
7def multiply_numbers(a, b):
8    return a * b
9
10
11# Test cases for add_numbers function
12assert add_numbers(2, 3) == 5
13assert add_numbers(-1, 1) == 0
14assert add_numbers(0, 0) == 0
15
16# Test cases for multiply_numbers function
17assert multiply_numbers(2, 3) == 6
18assert multiply_numbers(-1, 1) == -1
19assert multiply_numbers(0, 5) == 0
20
21print('All tests passed!')

xxxxxxxxxx

if __name__ == '__main__':

  # Python logic here

  def add_numbers(a, b):

    return a + b

​

  def multiply_numbers(a, b):

    return a * b

​

  def test_add_numbers():

    assert add_numbers(2, 3) == 5

    assert add_numbers(-1, 1) == 0

    assert add_numbers(0, 0) == 0

    print('add_numbers passed all tests')

​

  def test_multiply_numbers():

    assert multiply_numbers(2, 3) == 6

    assert multiply_numbers(-1, 1) == -1

    assert multiply_numbers(0, 5) == 0

    print('multiply_numbers passed all tests')

​

  test_add_numbers()

  test_multiply_numbers()