Why assertions verify expected behavior in Cypress - Test Execution Impact

Test Overview

This test opens a simple webpage, clicks a button, and verifies that the button text changes as expected. The assertion checks that the expected behavior occurs after the click.

Test Code - Cypress

Cypress

describe('Button click changes text', () => {
  it('should change button text after click', () => {
    cy.visit('https://example.cypress.io/commands/actions')
    cy.get('.action-btn').first().click()
    cy.get('.action-btn').first().should('have.text', 'Clicked!')
  })
})

Execution Trace - 5 Steps

Step	Action	System State	Assertion	Result
1	Test starts	Test runner initialized, no browser opened yet	—	PASS
2	Browser opens and navigates to https://example.cypress.io/commands/actions	Page loads with a list of action buttons visible	—	PASS
3	Find the first button with class 'action-btn'	Button element found with text 'Click me'	—	PASS
4	Click the found button	Button clicked, page reacts by changing button text	—	PASS
5	Assert the button text is now 'Clicked!'	Button text updated to 'Clicked!'	Verify button text equals 'Clicked!'	PASS

Failure Scenario

Failing Condition: Button text does not change to 'Clicked!' after click

Execution Trace Quiz - 3 Questions

What does the assertion in this test verify?

A That the button is visible on the page

B That the page URL is correct

C That the button text changes to 'Clicked!' after clicking

D That the button is disabled

Key Result

Assertions are essential because they confirm that the application behaves as expected after actions, helping catch errors early.

Practice

1. Why do we use assertions in Cypress tests?

easy

A. To change the app's data

B. To slow down the test execution

C. To skip parts of the test

D. To check if the app behaves as expected

Solution

1. Step 1: Understand the purpose of assertions

   Assertions are used to verify that the application behaves as expected during tests.

2. Step 2: Identify the correct purpose in options

   Only To check if the app behaves as expected states that assertions check expected behavior, which is correct.

3. Final Answer:

   To check if the app behaves as expected -> Option D

4. Quick Check:

   Assertions verify expected behavior = C [OK]

Hint: Assertions confirm expected results, not change behavior [OK]

Common Mistakes:

• Thinking assertions change app data
• Believing assertions slow tests down
• Confusing assertions with test flow control

2. Which of the following is the correct syntax to assert that a button with id submit is visible in Cypress?

easy

A. cy.get('submit').should('visible')

B. cy.find('#submit').assert('visible')

C. cy.get('#submit').should('be.visible')

D. cy.get('#submit').check('visible')

Solution

1. Step 1: Recall correct Cypress assertion syntax

   In Cypress, cy.get(selector).should('be.visible') checks visibility.

2. Step 2: Compare options with correct syntax

   cy.get('#submit').should('be.visible') matches the correct syntax exactly; others have wrong methods or missing quotes.

3. Final Answer:

   cy.get('#submit').should('be.visible') -> Option C

4. Quick Check:

   Correct assertion syntax = B [OK]

Hint: Use cy.get() with .should('be.visible') for visibility checks [OK]

Common Mistakes:

• Missing '#' for id selector
• Using wrong assertion method like check or assert
• Omitting quotes around assertion string

3. What will happen when this Cypress code runs?

cy.get('.message').should('contain.text', 'Success')

medium

A. Test passes if element with class 'message' contains text 'Success'

B. Test fails if element with class 'message' contains text 'Success'

C. Test passes regardless of element text

D. Test throws a syntax error

Solution

1. Step 1: Analyze the assertion syntax

   The code uses .should('contain.text', 'Success'), which is a valid Cypress assertion chainer.

2. Step 2: Determine test outcome

   The test passes if the element with class 'message' contains the text 'Success'; otherwise, it fails.

3. Final Answer:

   Test passes if element with class 'message' contains text 'Success' -> Option A

4. Quick Check:

   Valid 'contain.text' assertion = A [OK]

Hint: 'contain.text' is valid in Cypress for text content check [OK]

Common Mistakes:

• Thinking 'contain.text' is invalid
• Predicting pass/fail based on text presence
• Confusing with other assertion methods

4. Identify the error in this Cypress assertion:

cy.get('.title').should('have.text', Success)

medium

A. Missing quotes around 'Success' string

B. Wrong selector syntax

C. Incorrect assertion method 'have.text'

D. No error, code is correct

Solution

1. Step 1: Check the assertion syntax

   The text 'Success' must be a string, so it needs quotes around it.

2. Step 2: Identify the error in the code

   The code misses quotes around Success, causing a syntax error or undefined variable.

3. Final Answer:

   Missing quotes around 'Success' string -> Option A

4. Quick Check:

   String literals need quotes = A [OK]

Hint: Always put quotes around text in assertions [OK]

Common Mistakes:

• Forgetting quotes around string values
• Thinking selector syntax is wrong
• Misunderstanding assertion method names

5. You want to verify a checkbox with id agree is checked after clicking it. Which assertion correctly verifies this expected behavior?

hard

A. cy.get('#agree').click().should('have.value', 'checked')

B. cy.get('#agree').click().should('be.checked')

C. cy.get('#agree').click().should('contain.text', 'checked')

D. cy.get('#agree').click().should('be.visible')

Solution

1. Step 1: Understand the goal of the assertion

   We want to confirm the checkbox is checked after clicking it.

2. Step 2: Identify the correct assertion method

   The correct assertion is should('be.checked') which verifies checkbox state.

3. Step 3: Evaluate options

   cy.get('#agree').click().should('be.checked') uses be.checked, which is correct. The other options incorrectly check value, visibility, or text content.

4. Final Answer:

   cy.get('#agree').click().should('be.checked') -> Option B

5. Quick Check:

   should('be.checked') = D [OK]

Hint: Use .should('be.checked') to confirm checkbox is selected [OK]

Common Mistakes:

• Checking visibility instead of checked state
• Looking for text 'checked' inside checkbox
• Using value instead of checked property