JSON body in Postman - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this JSON validation test?

Given this JSON body sent in a POST request, what will the test assertion result be in Postman?

Postman

{
  "user": {
    "id": 123,
    "name": "Alice",
    "roles": ["admin", "editor"]
  }
}

// Test script snippet:
pm.test("User ID is 123", () => {
  pm.expect(pm.response.json().user.id).to.eql(123);
});

A Test fails due to syntax error in JSON body

B Test fails because user.id is a string, not a number

C Test passes because user.id equals 123

D Test fails because roles array is empty

💡 Hint

Check the data type of user.id in the JSON body.

The JSON body has user.id as a number 123, matching the assertion exactly, so the test passes.

❓ assertion

intermediate

Which assertion correctly checks if the JSON response contains a non-empty roles array?

You want to write a Postman test to verify the roles array in the JSON response is not empty. Which assertion is correct?

A pm.expect(pm.response.json().user.roles.length).to.be.above(0);

B pm.expect(pm.response.json().user.roles).to.eql([]);

C pm.expect(pm.response.json().user.roles).to.be.empty();

D pm.expect(pm.response.json().user.roles).to.have.lengthOf(0);

💡 Hint

Think about how to check array length is greater than zero.

Option A correctly asserts the roles array length is greater than zero, meaning it is not empty.

❓ locator

advanced

Identify the correct JSON path to access the user's second role

Given this JSON body: { "user": { "id": 123, "name": "Alice", "roles": ["admin", "editor"] } } Which JSON path correctly accesses the second role?

A user.roles[1]

B user.roles.1

C user.roles(1)

D user.roles[2]

💡 Hint

Remember JSON arrays are zero-indexed.

Option A uses correct zero-based indexing to access the second element at index 1.

🔧 Debug

advanced

Why does this Postman test fail when checking a JSON boolean value?

Test script: pm.test("Check active status", () => { pm.expect(pm.response.json().user.active).to.eql("true"); }); JSON response: { "user": { "active": true } } Why does the test fail?

A The test syntax is invalid and causes a runtime error

B The JSON response is missing the active field

C The JSON boolean true is case-sensitive and must be "True"

D The test compares boolean true to string "true", causing failure

💡 Hint

Check the data types compared in the assertion.

The test compares boolean true with string "true", which are different types, so the assertion fails.

❓ framework

expert

Which Postman test script correctly validates that the JSON response has a 'user' object with a 'name' property of type string?

Choose the test script that correctly checks the presence and type of 'name' inside 'user' in the JSON response.

A

pm.test("User name is string", () => {
  const jsonData = pm.response.json();
  pm.expect(jsonData.user.name).to.be.string();
});

B

pm.test("User name is string", () => {
  const jsonData = pm.response.json();
  pm.expect(jsonData.user).to.have.property('name').that.is.a('string');
});

C

pm.test("User name is string", () => {
  const jsonData = pm.response.json();
  pm.expect(jsonData.user.name).to.be.a('string');
});

D

pm.test("User name is string", () => {
  const jsonData = pm.response.json();
  pm.expect(typeof jsonData.user.name).to.eql('string');
});

💡 Hint

Check the chaining syntax for property and type assertions in Postman.

Option B uses Chai's 'have.property' with 'that.is.a' chaining correctly to check property existence and type.