Condition block in Postman - Build an Automation Script

Validate response status and content using condition block in Postman test script

Preconditions (2)

Step 1: Send a GET request to https://jsonplaceholder.typicode.com/posts/1

Step 2: In the Tests tab, write a condition block to check if the response status code is 200

Step 3: If status code is 200, assert that the response body contains a userId field with value 1

Step 4: If status code is not 200, assert that the response body contains an error message

✅ Expected Result: Test passes if status code is 200 and userId is 1; otherwise, test fails with appropriate error assertion

Automation Requirements - Postman test scripts (JavaScript)

Assertions Needed:

Assert response status code equals 200

Assert response body contains userId with value 1 when status is 200

Assert response body contains error message when status is not 200

Best Practices:

Use pm.response.to.have.status for status code assertion

Use pm.expect for assertions

Use if-else condition blocks to handle different response scenarios

Keep test scripts readable and maintainable

Automated Solution

Postman

pm.test('Condition block test for status and response body', function () {
    if (pm.response.code === 200) {
        pm.expect(pm.response.json()).to.have.property('userId', 1);
    } else {
        pm.expect(pm.response.text()).to.include('error');
    }
});

This test script uses a condition block to check the response status code.

If the status code is 200, it asserts that the JSON response has a property userId equal to 1.

If the status code is not 200, it asserts that the response text includes the word error.

This approach ensures the test adapts to different response scenarios and verifies the expected content accordingly.

Common Mistakes - 3 Pitfalls

Not checking the response status code before asserting response body

Using pm.response.json() without verifying response is JSON

Hardcoding assertions without condition blocks

Bonus Challenge

Now add data-driven testing with 3 different API endpoints and validate their status and response content using condition blocks

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