Response body array assertions in Postman - Test Execution Trace

Test Overview

This test sends a GET request to an API endpoint that returns a JSON array in the response body. It verifies that the response status is 200, the response body is an array, and that the array contains at least one object with a specific property value.

Test Code - Postman

Postman

pm.test("Status code is 200", () => {
    pm.response.to.have.status(200);
});

pm.test("Response body is an array", () => {
    const jsonData = pm.response.json();
    pm.expect(Array.isArray(jsonData)).to.be.true;
});

pm.test("Array contains an object with 'id' equal to 3", () => {
    const jsonData = pm.response.json();
    const found = jsonData.some(item => item.id === 3);
    pm.expect(found).to.be.true;
});

Execution Trace - 4 Steps

Step	Action	System State	Assertion	Result
1	Send GET request to API endpoint	Request sent, waiting for response	-	PASS
2	Receive response with status 200 and JSON body	Response received: status 200, body is JSON array	Check that response status is 200	PASS
3	Parse response body as JSON	Response body parsed into JavaScript array	Verify that parsed response is an array	PASS
4	Check if any object in array has 'id' equal to 3	Iterate over array items	Assert that at least one item has id === 3	PASS

Failure Scenario

Failing Condition: Response status is not 200, or response body is not an array, or no object with 'id' equal to 3 is found

Execution Trace Quiz - 3 Questions

What does the test verify about the response body?

A That the response body is a JSON array

B That the response body is a string

C That the response body is empty

D That the response body is a number

Key Result

Always verify the response status before checking the response body. When the response is expected to be an array, assert its type explicitly. Use array methods like 'some' to check for specific objects inside the array efficiently.