Test-driven development workflow in Ruby - Mini Project: Build & Apply

Test-driven development workflow

📖 Scenario: You are building a simple calculator program that adds two numbers. You will use test-driven development (TDD) to create the calculator step by step.

🎯 Goal: Create a Ruby program that adds two numbers using TDD. You will first write a test, then write the code to pass the test, and finally print the result.

📋 What You'll Learn

Create a test method named test_addition that checks if adding 2 and 3 equals 5

Create a method named add that takes two numbers and returns their sum

Call the add method with 2 and 3 and store the result in a variable named result

Print the value of result

💡 Why This Matters

🌍 Real World

Test-driven development helps programmers write reliable code by writing tests before the actual code. This reduces bugs and improves confidence.

💼 Career

Many software development jobs require knowledge of TDD to ensure code quality and maintainability.

1

Write the test method

Write a method named test_addition that uses raise to check if add(2, 3) equals 5. Use raise "Test failed" unless add(2, 3) == 5 inside the method.

Ruby

# Write the test method test_addition here
# Your code here

Need a hint?

Define test_addition method and use raise with a condition that calls add(2, 3) and checks if it equals 5.

2

Create the add method

Create a method named add that takes two parameters a and b and returns their sum using a + b.

Ruby

def test_addition
  raise "Test failed" unless add(2, 3) == 5
end

# Create the add method below
# Your code here

Need a hint?

Define add method with two parameters and return their sum.

3

Run the test and store the result

Call the test_addition method to run the test. Then call add(2, 3) and store the result in a variable named result.

Ruby

def test_addition
  raise "Test failed" unless add(2, 3) == 5
end

def add(a, b)
  a + b
end

# Run the test and store the result
# Your code here

Need a hint?

Call test_addition to run the test, then assign add(2, 3) to result.

4

Print the result

Print the value of the variable result using puts result.

Ruby

def test_addition
  raise "Test failed" unless add(2, 3) == 5
end

def add(a, b)
  a + b
end

test_addition
result = add(2, 3)

# Print the result
# Your code here

Need a hint?

Use puts result to display the sum.