Let and before hooks in Ruby - Mini Project: Build & Apply

Using Let and Before Hooks in Ruby Tests

📖 Scenario: You are writing tests for a simple Ruby class that manages a list of tasks. To keep your tests clean and organized, you will use let to define reusable variables and before hooks to set up common test conditions.

🎯 Goal: Build a small test suite using let to create a task list and before hooks to add tasks before each test runs.

📋 What You'll Learn

Create a let variable named task_list that initializes an empty array.

Create a before hook that adds the string 'Buy milk' to task_list.

Write a test that checks if task_list includes 'Buy milk'.

Write a test that adds 'Walk dog' to task_list and checks if both tasks are present.

💡 Why This Matters

🌍 Real World

Using <code>let</code> and <code>before</code> hooks is common in Ruby testing frameworks like RSpec to organize test data and setup steps efficiently.

💼 Career

Understanding these concepts helps you write clean, maintainable tests in Ruby projects, a valuable skill for Ruby developers and QA engineers.

1

Create a let variable for the task list

Write a let block named task_list that returns an empty array [].

Ruby

require 'rspec'

RSpec.describe 'Task List' do
  # Create a let block named task_list that returns []
  # Your code here
end

Need a hint?

Use let(:task_list) { [] } inside the RSpec.describe block.

2

Add a before hook to add a task

Add a before block that adds the string 'Buy milk' to task_list using task_list << 'Buy milk'.

Ruby

require 'rspec'

RSpec.describe 'Task List' do
  let(:task_list) { [] }

  # Add a before block that adds 'Buy milk' to task_list
  # Your code here
end

Need a hint?

Use before do ... end and inside it add task_list << 'Buy milk'.

3

Write a test to check the initial task

Write an it block with description 'includes Buy milk' that expects task_list to include 'Buy milk' using expect(task_list).to include('Buy milk').

Ruby

require 'rspec'

RSpec.describe 'Task List' do
  let(:task_list) { [] }

  before do
    task_list << 'Buy milk'
  end

  # Write an it block named 'includes Buy milk' that checks task_list includes 'Buy milk'
  # Your code here
end

Need a hint?

Use it 'includes Buy milk' do ... end and inside use expect(task_list).to include('Buy milk').

4

Write a test to add and check multiple tasks

Write an it block with description 'adds Walk dog and checks both tasks' that adds 'Walk dog' to task_list and expects task_list to include both 'Buy milk' and 'Walk dog' using two expect statements.

Ruby

require 'rspec'

RSpec.describe 'Task List' do
  let(:task_list) { [] }

  before do
    task_list << 'Buy milk'
  end

  it 'includes Buy milk' do
    expect(task_list).to include('Buy milk')
  end

  # Write an it block named 'adds Walk dog and checks both tasks'
  # Add 'Walk dog' to task_list and check both tasks are included
  # Your code here
end

Need a hint?

Inside the it block, add task_list << 'Walk dog' and two expect lines to check both tasks.