Child commands in Cypress - Build an Automation Script

Verify child elements using Cypress child commands

Preconditions (1)

Step 1: Open the web page at 'http://localhost:3000/items'.

Step 2: Locate the container element with id 'item-list'.

Step 3: Within this container, find all child elements with the class 'item'.

Step 4: Verify that there are exactly 5 child elements with class 'item'.

Step 5: For the first child element, verify it contains the text 'Item 1'.

Step 6: For the last child element, verify it contains the text 'Item 5'.

✅ Expected Result: The container with id 'item-list' has exactly 5 child elements with class 'item'. The first child contains text 'Item 1' and the last child contains text 'Item 5'.

Automation Requirements - Cypress

Assertions Needed:

Assert the number of child elements with class 'item' is 5

Assert the first child element contains text 'Item 1'

Assert the last child element contains text 'Item 5'

Best Practices:

Use cy.get() to locate parent container

Use .children() to get child elements

Use .should() for assertions

Avoid hardcoding XPath selectors

Use explicit and clear selectors (id, class)

Chain commands properly to maintain Cypress flow

Automated Solution

Cypress

describe('Child commands test', () => {
  beforeEach(() => {
    cy.visit('http://localhost:3000/items');
  });

  it('should verify child elements inside #item-list', () => {
    cy.get('#item-list')
      .children('.item')
      .should('have.length', 5)
      .first()
      .should('contain.text', 'Item 1');

    cy.get('#item-list')
      .children('.item')
      .last()
      .should('contain.text', 'Item 5');
  });
});

The test starts by visiting the target URL in the beforeEach hook to ensure a fresh page load before each test.

We use cy.get('#item-list') to select the container by its id, which is a reliable and clear selector.

Then, .children('.item') fetches all direct child elements with the class item inside the container.

We assert the number of these child elements is exactly 5 using .should('have.length', 5).

Next, we check the first child element contains the text 'Item 1' using .first().should('contain.text', 'Item 1').

Similarly, we check the last child element contains the text 'Item 5' using .last().should('contain.text', 'Item 5').

This approach uses Cypress chaining and child commands properly, making the test clear, maintainable, and reliable.

Common Mistakes - 4 Pitfalls

{'mistake': "Using cy.get('.item') directly instead of using .children() from the parent container", 'why_bad': 'This can select elements outside the intended container, leading to false positives or negatives.', 'correct_approach': 'Always scope child element selection by first getting the parent container, then using .children() to get direct children.'}

{'mistake': 'Using hardcoded XPath selectors like cy.xpath(\'//div[@id="item-list"]//div[@class="item"]\')', 'why_bad': 'XPath selectors are less readable and harder to maintain compared to CSS selectors in Cypress.', 'correct_approach': 'Use CSS selectors with cy.get() and .children() for better readability and maintainability.'}

Not chaining commands properly and calling cy.get() multiple times unnecessarily

Using .find() instead of .children() when only direct children are needed

Bonus Challenge

Now add data-driven testing with 3 different containers each having different numbers of child items and verify their counts and first/last item texts.

Show Hint

Practice

1. What does the .find() command do in Cypress testing?

easy

A. It clicks on an element.

B. It types text into an input field.

C. It waits for a page to load.

D. It locates child elements inside a parent element.

Solution

1. Step 1: Understand the purpose of .find()

   The .find() command is used to search for elements inside another element, meaning it looks for child elements.

2. Step 2: Compare with other commands

   Commands like .click(), .type(), and .wait() perform actions or wait, but do not locate child elements.

3. Final Answer:

   It locates child elements inside a parent element. -> Option D

4. Quick Check:

   .find() locates children = B [OK]

Hint: Remember: .find() searches inside a parent element [OK]

Common Mistakes:

• Confusing .find() with .click() or .type()
• Thinking .find() waits for elements
• Using .find() without a parent element

2. Which of the following is the correct syntax to find a button inside a div with class container using Cypress?

easy

A. cy.get('.container').find('button')

B. cy.find('.container').get('button')

C. cy.get('button').find('.container')

D. cy.find('button').get('.container')

Solution

1. Step 1: Understand chaining commands in Cypress

   First, cy.get() selects the parent element. Then, .find() locates child elements inside it.

2. Step 2: Analyze each option

   cy.get('.container').find('button') correctly uses cy.get('.container') to select the parent, then .find('button') to find the child button. Other options misuse the order or commands.

3. Final Answer:

   cy.get('.container').find('button') -> Option A

4. Quick Check:

   Parent first with get(), then child with find() = A [OK]

Hint: Use cy.get() first, then .find() for child elements [OK]

Common Mistakes:

• Swapping .get() and .find() order
• Using .find() without cy.get() first
• Selecting child before parent

3. What will the following Cypress code select?

cy.get('ul.menu').find('li.active').should('have.length', 2)

medium

A. It selects all li elements inside ul.menu with class active and checks there are 2.

B. It selects 2 ul elements with class menu.

C. It clicks on the first li.active element.

D. It types '2' into the ul.menu element.

Solution

1. Step 1: Understand the selector chain

   cy.get('ul.menu') selects the ul element with class menu. Then .find('li.active') finds li children with class active.

2. Step 2: Understand the assertion

   .should('have.length', 2) asserts that exactly 2 such li.active elements exist inside the ul.menu.

3. Final Answer:

   It selects all li elements inside ul.menu with class active and checks there are 2. -> Option A

4. Quick Check:

   Find children with class and check count = A [OK]

Hint: Find children, then assert count with .should('have.length') [OK]

Common Mistakes:

• Confusing parent and child selectors
• Thinking it clicks or types instead of asserting
• Misreading the assertion purpose

4. Identify the error in this Cypress code snippet:

cy.find('.list').get('li').should('have.length', 3)

medium

A. There is no error; the code is correct.

B. The selector '.list' is invalid.

C. The order of commands is incorrect; .get() should come before .find().

D. The assertion .should('have.length', 3) is not valid.

Solution

1. Step 1: Check command order

   cy.find() is not a valid starting command. cy.get() must be used first to select the parent element.

2. Step 2: Correct usage

   The correct order is cy.get('.list').find('li') to find li children inside the element with class list.

3. Final Answer:

   The order of commands is incorrect; .get() should come before .find(). -> Option C

4. Quick Check:

   Use cy.get() first, then .find() = D [OK]

Hint: Always start with cy.get() before .find() [OK]

Common Mistakes:

• Starting with .find() instead of cy.get()
• Assuming .find() works alone
• Ignoring command chaining rules

5. You want to verify that a form with id login contains exactly 3 input fields that are visible. Which Cypress code correctly uses child commands to do this?

hard

A. cy.find('#login').get('input:visible').should('have.length', 3)

B. cy.get('#login').find('input:visible').should('have.length', 3)

C. cy.get('#login').find('input').should('have.length', 3).and('be.visible')

D. cy.get('input:visible').find('#login').should('have.length', 3)

Solution

1. Step 1: Select the parent form element

   Use cy.get('#login') to select the form with id 'login'.

2. Step 2: Find visible input children and assert count

   Use .find('input:visible') to get visible input fields inside the form, then assert there are exactly 3 with .should('have.length', 3).

3. Final Answer:

   cy.get('#login').find('input:visible').should('have.length', 3) -> Option B

4. Quick Check:

   Parent get(), then find visible inputs, then check length = C [OK]

Hint: Chain get() then find(':visible') before asserting length [OK]

Common Mistakes:

• Using .find() before cy.get()
• Checking visibility after length assertion
• Incorrect selector order