Dynamic test data generation in Cypress - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to generate a random email for testing.

Cypress

const randomEmail = `user$[1]@example.com`;

Drag options to blanks, or click blank then click option'

AMath.random().toString(36).substring(2, 10)

BDate.now()

Cnew Date()

DMath.floor(Math.random())

Attempts:

3 left

💡 Hint

Common Mistakes

Using Date.now() alone may cause collisions if tests run quickly.

Using new Date() returns an object, not a string.

Math.floor(Math.random()) always returns 0.

Using Math.random().toString(36).substring(2, 10) generates a random string suitable for unique emails.

2fill in blank

medium

Complete the code to create a random username with a prefix.

Cypress

const username = `user_$[1]`;

Drag options to blanks, or click blank then click option'

AMath.random()

BMath.floor(Math.random() * 10000)

CDate.now()

Dnew Date().getTime()

Attempts:

3 left

💡 Hint

Common Mistakes

Using Math.random() alone returns a decimal, not suitable for usernames.

Using Date.now() or getTime() may cause long numbers.

Math.floor(Math.random() * 10000) generates a random integer between 0 and 9999, good for usernames.

3fill in blank

hard

Fix the error in the code to generate a random password of length 8.

Cypress

const password = Array.from({ length: 8 }, () => [1]).join('');

Drag options to blanks, or click blank then click option'

AMath.random().toString(36).charAt(8)

BMath.random().toString(36).charAt(0)

CMath.random().toString(36).charAt(10)

DMath.random().toString(36).charAt(2)

Attempts:

3 left

💡 Hint

Common Mistakes

Using charAt(0) returns '0' always.

Using charAt(10) or charAt(8) may return empty string.

Using charAt(2) gets a valid character from the random string. charAt(0) is '0', and higher indexes may be undefined.

4fill in blank

hard

Fill both blanks to create a dynamic test user object with random id and email.

Cypress

const testUser = { id: [1], email: `test$[2]@mail.com` };

Drag options to blanks, or click blank then click option'

AMath.floor(Math.random() * 1000)

BMath.random()

CDate.now()

DMath.random().toString(36).substring(2, 8)

Attempts:

3 left

💡 Hint

Common Mistakes

Using Math.random() directly for id gives a decimal.

Using Date.now() for email part creates long numbers.

Use Math.floor(Math.random() * 1000) for a random id number and Math.random().toString(36).substring(2, 8) for a random email string.

5fill in blank

hard

Fill all three blanks to generate a dynamic test data object with username, password, and email.

Cypress

const testData = { username: `user$[1]`, password: Array.from({ length: 6 }, () => [2]).join(''), email: `email$[3]@test.com` };

Drag options to blanks, or click blank then click option'

AMath.floor(Math.random() * 5000)

BMath.random().toString(36).charAt(2)

CMath.random().toString(36).substring(2, 6)

DDate.now()

Attempts:

3 left

💡 Hint

Common Mistakes

Using Math.random() directly for username causes decimals.

Using charAt(0) for password returns '0' always.

Using Date.now() for email part creates long numbers.

Use Date.now() for username suffix for uniqueness, charAt(2) for password characters, and substring(2, 6) for email random part.

Practice

1. What is the main benefit of using dynamic test data generation in Cypress tests?

easy

A. It creates unique data for each test run to avoid conflicts.

B. It makes tests run slower by adding delays.

C. It hardcodes values to ensure consistency.

D. It disables assertions to speed up tests.

Solution

1. Step 1: Understand dynamic data purpose

   Dynamic test data generation creates fresh data each time to prevent clashes with existing data.

2. Step 2: Compare options

   Only It creates unique data for each test run to avoid conflicts. describes this benefit correctly; others describe incorrect or unrelated effects.

3. Final Answer:

   It creates unique data for each test run to avoid conflicts. -> Option A

4. Quick Check:

   Dynamic data = unique per run [OK]

Hint: Dynamic data means fresh unique values each test run [OK]

Common Mistakes:

• Thinking dynamic data slows tests
• Confusing dynamic with hardcoded data
• Believing dynamic data disables assertions

2. Which of the following is the correct way to generate a random email in Cypress using JavaScript template literals?

easy

A. const email = user${Math.random()}@test.com;

B. const email = 'user' + Math.random() + '@test.com';

C. const email = `user+Math.random()@test.com`;

D. const email = `user${Math.random()}@test.com`;

Solution

1. Step 1: Identify correct template literal syntax

   Template literals use backticks and ${} to embed expressions, so `user${Math.random()}@test.com` is correct.

2. Step 2: Check other options

   const email = 'user' + Math.random() + '@test.com'; uses string concatenation, which works but is not template literals. const email = user${Math.random()}@test.com; misses backticks. const email = `user+Math.random()@test.com`; treats Math.random() as string literal.

3. Final Answer:

   const email = `user${Math.random()}@test.com`; -> Option D

4. Quick Check:

   Template literals use backticks and ${} [OK]

Hint: Template literals use backticks and ${expression} [OK]

Common Mistakes:

• Using quotes instead of backticks for template literals
• Forgetting ${} around expressions
• Treating expressions as plain text

3. Given the Cypress code snippet:

const randomId = Math.floor(Math.random() * 1000);
cy.get('#user-input').type(`user${randomId}`);
cy.get('#submit-btn').click();
cy.get('#result').should('contain', `user${randomId}`);

What will the assertion check?

medium

A. That the element with id 'result' contains a random number only.

B. That the element with id 'result' contains the text 'user' only.

C. That the element with id 'result' contains the exact text 'user' plus the random number generated.

D. That the element with id 'result' contains the string 'randomId'.

Solution

1. Step 1: Understand variable usage in template literals

   The variable randomId is generated once and used in the string `user${randomId}` for typing and assertion.

2. Step 2: Analyze assertion

   The assertion checks if '#result' contains the exact string 'user' concatenated with the random number stored in randomId.

3. Final Answer:

   That the element with id 'result' contains the exact text 'user' plus the random number generated. -> Option C

4. Quick Check:

   Assertion checks full dynamic string [OK]

Hint: Assertions check exact dynamic string used in test [OK]

Common Mistakes:

• Assuming assertion checks only 'user' text
• Thinking random number is checked alone
• Confusing variable name with string literal

4. Identify the error in this Cypress test code that tries to generate a random username:

const username = 'user' + Math.random;
cy.get('#username').type(username);
cy.get('#submit').click();

medium

A. The username variable should be declared inside the test only.

B. Math.random is missing parentheses, so it is a function reference, not a number.

C. The selector '#username' is invalid and should be '.username'.

D. The click command is missing parentheses.

Solution

1. Step 1: Check Math.random usage

   Math.random is a function and must be called with parentheses to get a number. Without (), username becomes 'user' plus function reference string.

2. Step 2: Verify other parts

   Selectors and click command syntax are correct. The main error is missing parentheses on Math.random.

3. Final Answer:

   Math.random is missing parentheses, so it is a function reference, not a number. -> Option B

4. Quick Check:

   Call Math.random() with () to get number [OK]

Hint: Always call Math.random() with parentheses [OK]

Common Mistakes:

• Forgetting parentheses on Math.random
• Misreading selector syntax
• Thinking click needs extra parentheses

5. You want to generate a dynamic user object with unique email and username for each Cypress test run. Which approach correctly creates this object and uses it in a test?

const user = {
  username: `user${Math.floor(Math.random() * 10000)}`,
  email: `email${Math.floor(Math.random() * 10000)}@test.com`
};

cy.visit('/signup');
cy.get('#username').type(user.username);
cy.get('#email').type(user.email);
cy.get('#submit').click();
cy.get('#welcome').should('contain', user.username);

hard

A. This approach correctly generates unique user data and uses it in the test assertions.

B. This approach fails because Math.random() should not be used for test data.

C. This approach is incorrect because user object must be inside cy.then() callback.

D. This approach is wrong because template literals cannot be used inside objects.

Solution

1. Step 1: Analyze user object creation

   The user object uses template literals with Math.floor(Math.random() * 10000) to create unique username and email strings before the test runs.

2. Step 2: Check usage in Cypress commands

   The test types the dynamic username and email into inputs, clicks submit, and asserts the welcome message contains the username, which is valid and correct.

3. Final Answer:

   This approach correctly generates unique user data and uses it in the test assertions. -> Option A

4. Quick Check:

   Dynamic object with random values used correctly [OK]

Hint: Create dynamic objects before test, then use in commands [OK]

Common Mistakes:

• Thinking Math.random() is disallowed for test data
• Believing object must be inside cy.then() unnecessarily
• Misunderstanding template literal usage inside objects