Write Better Code: Master Test-Driven Development (TDD)

What is TDD?

Test Driven Development (TDD) is a programming approach that flips the usual coding process on its head. Instead of writing your code first and testing it later, you start by writing tests for your code before you even create it.

Here's how it works:

• Write a test: Begin by creating a test that defines how your code should behave.
• Run the test: It will fail because you haven't written the code yet.
• Write the code: Create the minimum amount of code to pass the test.
• Run the test again: If it passes, great! If not, fix your code.
• Refactor: Clean up and improve your code while ensuring the test still passes.
• Repeat: Continue this cycle for each new feature or function.

Benefits of TDD

• Ensures code works as intended
• Helps catch bugs early
• Encourages clear thinking about code requirements
• Makes it easier to refactor and improve code
• Provides built-in documentation through tests

TDD might seem counterintuitive at first, but it can lead to more reliable and maintainable code. Give it a try in your next project.

Example

Write the test first: Before coding, write a test that defines the expected behavior.
Example: You're building a calculator app. Write a test for addition:

def test_addition
  assert_equal 5, Calculator.add(2, 3)
end

Run the test (it should fail): Run the test before writing any code. It should fail because the functionality doesn't exist yet.

Example: Running the test shows a failure because the Calculator class and add method don't exist.

Write the minimum code to pass the test: Implement just enough code to make the test pass.

Example: Create the Calculator class with an add method:

class Calculator
  def self.add(a, b)
    a + b
  end
end

Run the test again (it should pass): The test should now pass with the implemented code.

Example: Running the test shows a success because the add method works correctly.

Refactor if necessary: Improve the code while ensuring the test still passes.

Example: No refactoring needed for this simple case, but you might optimize for larger numbers later.

Repeat for new features: Continue this cycle for each new feature or functionality.

Example: Next, write a test for subtraction, then implement it, and so on.