Using Chai assertion library in Postman - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the Chai assertion library used for in Postman tests?

Chai is used to write clear and readable assertions to check if API responses meet expected conditions during Postman tests.

beginner

How do you write a basic assertion to check if a response status code is 200 using Chai in Postman?

pm.test('Status code is 200', function () { pm.response.to.have.status(200); });

intermediate

What does the Chai assertion 'expect(response).to.have.property("name")' check for?

It checks that the response object has a property called "name".

intermediate

Explain the difference between 'expect' and 'assert' styles in Chai.

Both are assertion styles in Chai. 'expect' reads like natural language (e.g., expect(value).to.equal(5)), while 'assert' uses functions (e.g., assert.equal(value, 5)). Both check conditions but differ in syntax.

beginner

How can you check if a JSON response body contains a specific string using Chai in Postman?

Use: pm.test('Body contains string', function () { pm.expect(pm.response.text()).to.include('expected string'); });

Which Chai assertion checks if a response status is 404?

A pm.response.status(404);

B pm.response.to.be.status(404);

C pm.response.to.have.status(404);

D pm.response.has.status(404);

The correct syntax to check status code is pm.response.to.have.status(404);

What does this assertion check? pm.expect(responseJson.success).to.be.true;

A That responseJson.success is a string

B That responseJson.success is true

C That responseJson.success is false

D That responseJson.success exists

It checks that the success property in responseJson is exactly true.

Which Chai style uses natural language syntax?

A expect

B assert

C should

D verify

'expect' style reads like natural language, e.g., expect(value).to.equal(5).

How do you check if response body contains the word 'success'?

A pm.expect(pm.response.text()).to.include('success');

B pm.response.to.have.body('success');

C pm.expect(pm.response.body).to.have.string('success');

D pm.response.body.includes('success');

pm.expect(pm.response.text()).to.include('success'); correctly checks if the response text contains 'success'.

What is the purpose of pm.test() in Postman tests?

A To set environment variables

B To send an API request

C To log response data

D To define a test case with a name and function

pm.test() defines a test with a descriptive name and a function containing assertions.

Describe how to write a Chai assertion in Postman to verify the response status code and a JSON property value.

Think about checking status first, then accessing JSON body and asserting a property.

Explain the difference between 'expect' and 'assert' styles in Chai and when you might prefer one over the other.

Consider how each style reads and how easy it is to understand.