RSpec describe and it blocks in Ruby - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of nested describe and it blocks

What will be the output when running this RSpec test code?

Ruby

RSpec.describe 'Calculator' do
  describe '#add' do
    it 'adds two numbers' do
      expect(2 + 3).to eq(5)
    end
  end

  describe '#subtract' do
    it 'subtracts two numbers' do
      expect(5 - 3).to eq(2)
    end
  end
end

A 2 examples, 0 failures

B 1 example, 0 failures

C 2 examples, 2 failures

D 0 examples, 0 failures

💡 Hint

Count the number of it blocks inside all describe blocks.

There are two it blocks, each defining one example. Both expectations are correct, so 2 examples run with 0 failures.

🧠 Conceptual

intermediate

Purpose of describe and it blocks in RSpec

What is the main purpose of the describe and it blocks in RSpec?

A <code>describe</code> defines variables; <code>it</code> groups tests

B <code>describe</code> runs tests; <code>it</code> sets up variables

C <code>describe</code> groups tests; <code>it</code> defines individual test examples

D <code>describe</code> is for assertions; <code>it</code> is for setup

💡 Hint

Think about how you organize tests and what runs as a test.

describe is used to group related tests, while it defines each test example that runs an expectation.

🔧 Debug

advanced

Identify the error in this RSpec test code

What error will this RSpec code produce when run?

Ruby

RSpec.describe 'Math' do
  it 'multiplies numbers' do
    expect(2 * 3).to eq 6
  end

  it 'divides numbers' do
    expect(10 / 2).to eq(5)
  end
end

A SyntaxError due to missing closing parenthesis

B No error, tests pass

C NameError for undefined method

D RuntimeError due to division by zero

💡 Hint

Check the parentheses in the second it block.

The second it block has a missing closing parenthesis in the expect statement, causing a SyntaxError.

❓ Predict Output

advanced

Output of nested it blocks inside describe

What will be the output of this RSpec code?

Ruby

RSpec.describe 'String' do
  it 'checks length' do
    expect('hello'.length).to eq(5)

    it 'nested it block' do
      expect('world'.upcase).to eq('WORLD')
    end
  end
end

A SyntaxError: nested 'it' blocks are not allowed

B 2 examples, 0 failures

C 0 examples, 0 failures

D 1 example, 1 failure

💡 Hint

Consider if RSpec allows it blocks inside other it blocks.

RSpec does not allow nesting it blocks inside other it blocks. Only one example is registered. When run, the inner `it` call raises a runtime error, resulting in 1 example, 1 failure.

🧠 Conceptual

expert

How does RSpec handle multiple describe blocks with the same name?

If you have multiple describe blocks with the same description string in RSpec, how does RSpec treat them?

A RSpec merges them into one group and runs examples once

B RSpec treats them as separate groups and runs all their examples

C RSpec runs only the first describe block and ignores others

D RSpec raises an error about duplicate describe blocks

💡 Hint

Think about how RSpec organizes tests by describe blocks.

RSpec treats each describe block independently, even if they have the same description string, running all examples in all blocks.