expect() for BDD assertions in Cypress - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of expect() in BDD assertions?

expect() is used to write readable tests that check if a value meets certain conditions. It helps confirm that the app behaves as expected.

beginner

How do you check if a number is equal to 5 using expect()?

You write expect(number).to.equal(5). This asserts that the variable number should be exactly 5.

beginner

What does expect(value).to.be.true check?

It checks that the value is exactly true. This is useful for boolean conditions.

beginner

How can you check if a string contains a word using expect()?

Use expect(string).to.include('word'). This checks if the string has the word anywhere inside it.

beginner

What happens if an expect() assertion fails during a test?

The test will stop and show a failure message explaining which check did not pass. This helps find bugs quickly.

Which expect() assertion checks if a value is greater than 10?

A expect(value).to.be.greaterThan(10)

B expect(value).to.be.above(10)

C expect(value).to.equal(10)

D expect(value).to.include(10)

to.be.above(10) is the correct syntax in Cypress BDD assertions to check if a value is greater than 10.

What does expect(array).to.have.length(3) verify?

A Array has at least 3 items

B Array is empty

C Array contains the number 3

D Array has exactly 3 items

This assertion checks that the array length is exactly 3.

How do you assert that a variable isActive is false?

A expect(isActive).to.be.false

B expect(isActive).to.equal(true)

C expect(isActive).to.be.true

D expect(isActive).to.include(false)

to.be.false checks that the value is exactly false.

Which assertion checks if a string starts with 'Hello'?

A expect(str).to.have.length('Hello')

B expect(str).to.include('Hello')

C expect(str).to.startWith('Hello')

D expect(str).to.equal('Hello')

to.startWith('Hello') checks if the string begins with 'Hello'.

What is the main benefit of using expect() in tests?

A To check if code meets expected results clearly

B To write complex loops

C To style the webpage

D To create variables

expect() helps write clear checks that confirm code works as expected.

Explain how expect() is used in Cypress to verify that a button is visible on the page.

Think about how you find elements and check their state.

Describe the difference between expect(value).to.equal() and expect(value).to.include().

Consider whole vs part matching.

Practice

1. What is the main purpose of using expect() in Cypress tests?

easy

A. To log messages in the console

B. To run the test suite faster

C. To select elements on the page

D. To check if the actual value matches the expected value

Solution

1. Step 1: Understand the role of expect()

   expect() is used to compare actual results with expected results in tests.

2. Step 2: Identify the correct purpose

   It helps verify if the app behaves as expected by checking values.

3. Final Answer:

   To check if the actual value matches the expected value -> Option D

4. Quick Check:

   expect() compares values [OK]

Hint: Remember: expect() checks actual vs expected values [OK]

Common Mistakes:

• Thinking expect() runs tests
• Confusing expect() with element selectors
• Using expect() to log messages

2. Which of the following is the correct syntax to assert that a variable count equals 5 using expect() in Cypress?

easy

A. expect(count).to.equal(5);

B. expect(count).toBe(5);

C. expect(count).equals(5);

D. expect(count).is(5);

Solution

1. Step 1: Recall Cypress BDD assertion syntax

   Cypress uses Chai assertions where to.equal() checks equality.

2. Step 2: Identify the correct syntax

   expect(count).to.equal(5); is the correct way to assert equality.

3. Final Answer:

   expect(count).to.equal(5); -> Option A

4. Quick Check:

   Use to.equal() for equality [OK]

Hint: Use to.equal() for equality checks in Cypress [OK]

Common Mistakes:

• Using toBe() which is Jest syntax
• Using equals() without to
• Using is() which is invalid

3. What will be the result of this Cypress assertion?

const title = 'Welcome';
expect(title).to.have.length(7);

medium

A. Test passes because 'Welcome' has 7 characters

B. Test fails because length is checked incorrectly

C. Syntax error due to wrong method

D. Test passes but length is 6

Solution

1. Step 1: Check the string length

   The string 'Welcome' has exactly 7 characters.

2. Step 2: Understand the assertion

   to.have.length(7) correctly asserts the string length is 7.

3. Final Answer:

   Test passes because 'Welcome' has 7 characters -> Option A

4. Quick Check:

   String length 7 matches assertion [OK]

Hint: Count characters to verify length assertions [OK]

Common Mistakes:

• Assuming length counts words, not characters
• Confusing length with array length
• Using wrong assertion method

4. Identify the error in this Cypress assertion:

expect(user.name).to.equals('Alice');

medium

A. Missing parentheses after user.name

B. Incorrect method name; should be to.equal

C. Should use expect(user).to.equal('Alice')

D. No error; assertion is correct

Solution

1. Step 1: Check the assertion method

   The correct Chai assertion method is to.equal, not to.equals.

2. Step 2: Confirm syntax correctness

   Using to.equals causes a runtime error because it is not defined.

3. Final Answer:

   Incorrect method name; should be to.equal -> Option B

4. Quick Check:

   Use to.equal, not to.equals [OK]

Hint: Remember: method is to.equal, not to.equals [OK]

Common Mistakes:

• Using to.equals instead of to.equal
• Confusing property access syntax
• Assuming expect needs parentheses after property

5. You want to check that an array items contains the string 'apple' using expect(). Which assertion correctly tests this?

hard

A. expect(items).to.equal('apple');

B. expect(items).to.have.length('apple');

C. expect(items).to.include('apple');

D. expect(items).to.contain.length('apple');

Solution

1. Step 1: Understand the goal

   You want to check if 'apple' is inside the array items.

2. Step 2: Choose the correct assertion

   to.include('apple') checks if the array contains that element.

3. Final Answer:

   expect(items).to.include('apple'); -> Option C

4. Quick Check:

   Use to.include() to check array contents [OK]

Hint: Use to.include() to check if array has an item [OK]

Common Mistakes:

• Using to.equal() which checks full equality
• Using length assertions incorrectly
• Combining contain and length wrongly