Default and conditional responses in Postman - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a default response in Postman mock servers?

A default response is the response that Postman returns when no conditional response matches the request. It acts like a fallback or catch-all answer.

beginner

How do conditional responses work in Postman mock servers?

Conditional responses are set up with rules that check parts of the request, like URL, headers, or body. If the request matches the condition, Postman returns the matching response instead of the default.

intermediate

Why use conditional responses in API testing?

Conditional responses let you simulate different server behaviors based on request details. This helps test how your app handles various scenarios without needing a real server.

intermediate

What happens if no default response is set in a Postman mock server?

If no default response is set and no conditional response matches, the mock server returns a 404 Not Found error because it doesn't know how to respond.

advanced

How can you prioritize multiple conditional responses in Postman?

Postman evaluates conditional responses in the order they are listed. The first matching condition is used, so order your conditions from most specific to least specific.

What does a default response do in a Postman mock server?

A Returns when no conditional response matches

B Overrides all conditional responses

C Is only used for POST requests

D Is the first conditional response checked

The default response acts as a fallback when no conditional response matches the request.

Which request part can you NOT use to create a conditional response in Postman?

A Request URL

B Request headers

C Request body

D Response status code

Conditional responses are based on request details, not on response status codes.

If multiple conditional responses match a request, which one does Postman use?

A The last one listed

B The first one listed

C The one with the highest status code

D A random one

Postman uses the first matching conditional response it finds in the list.

What status code does Postman return if no response matches and no default is set?

A 404 Not Found

B 500 Internal Server Error

C 200 OK

D 400 Bad Request

Without a matching response or default, Postman returns 404 Not Found.

Why are conditional responses useful in API testing?

A They speed up the server

B They encrypt the response data

C They simulate different server behaviors based on requests

D They automatically fix bugs

Conditional responses let you test how your app handles different server replies by simulating various scenarios.

Explain how default and conditional responses work together in a Postman mock server.

Think about how the server decides which response to send back.

Describe a real-life situation where using conditional responses in Postman would help your testing.

Imagine testing an app that behaves differently based on user actions.

Practice

1. What is the main purpose of using default and conditional responses in Postman tests?

easy

A. To send multiple requests at the same time

B. To change the API endpoint dynamically

C. To check different API responses in one test script

D. To automatically generate API documentation

Solution

1. Step 1: Understand the role of conditional responses

   Conditional responses allow testing different API replies based on conditions in one place.

2. Step 2: Identify the main purpose

   This helps verify various outcomes without writing separate tests for each response.

3. Final Answer:

   To check different API responses in one test script -> Option C

4. Quick Check:

   Default and conditional responses = test multiple replies [OK]

Hint: Think: one test script, many response checks [OK]

Common Mistakes:

• Confusing response testing with sending requests
• Assuming it changes API endpoints
• Mixing testing with documentation generation

2. Which of the following is the correct syntax to write a conditional test in Postman to check if the response status is 200?

easy

A. pm.test('Status is 200', () => { if (pm.response.code === 200) { pm.expect(true).to.be.true; } });

B. pm.test('Status is 200', () => { pm.expect(pm.response.code).to.equal(200); });

C. pm.test('Status is 200', () => pm.response.code == 200);

D. pm.test('Status is 200', () => { if (pm.response.status == 200) pm.expect(true); });

Solution

1. Step 1: Review Postman test syntax

   Postman uses pm.test with a callback function and pm.expect for assertions.

2. Step 2: Identify correct assertion for status code

   pm.expect(pm.response.code).to.equal(200) correctly asserts status code equals 200.

3. Final Answer:

   pm.test('Status is 200', () => { pm.expect(pm.response.code).to.equal(200); }); -> Option B

4. Quick Check:

   pm.expect with .to.equal(200) = correct syntax [OK]

Hint: Use pm.expect with .to.equal for exact value checks [OK]

Common Mistakes:

• Using '==' instead of .to.equal() in assertions
• Checking pm.response.status instead of pm.response.code
• Not calling pm.expect properly inside pm.test

3. Given this Postman test code, what will be the test result if the response status is 404?

pm.test('Check response', () => {
  if (pm.response.code === 200) {
    pm.expect(pm.response.json().success).to.be.true;
  } else {
    pm.expect(pm.response.code).to.equal(404);
  }
});

medium

A. Test passes because status is 404 and matches else condition

B. Test fails because success property is missing

C. Test throws an error due to missing JSON body

D. Test passes only if success is true

Solution

1. Step 1: Analyze the if-else condition with status 404

   Status 404 triggers the else block which asserts pm.response.code equals 404.

2. Step 2: Check assertion in else block

   pm.expect(pm.response.code).to.equal(404) will pass since status is 404.

3. Final Answer:

   Test passes because status is 404 and matches else condition -> Option A

4. Quick Check:

   404 status triggers else assertion = pass [OK]

Hint: Match status code to correct if/else branch [OK]

Common Mistakes:

• Assuming test fails due to missing success property
• Thinking JSON parsing fails on 404
• Ignoring else block assertions

4. Identify the error in this Postman test script that checks for a 201 status or a 400 error:

pm.test('Status check', () => {
  if (pm.response.code = 201) {
    pm.expect(pm.response.code).to.equal(201);
  } else if (pm.response.code = 400) {
    pm.expect(pm.response.json().error).to.exist;
  }
});

medium

A. No else block to handle other status codes

B. Missing pm.expect in the first if block

C. Incorrect JSON parsing method

D. Using assignment '=' instead of comparison '===' in if conditions

Solution

1. Step 1: Check if condition syntax

   The code uses '=' which assigns value instead of '===' for comparison.

2. Step 2: Understand impact of assignment in conditions

   Assignment always returns true, causing logic errors and wrong test behavior.

3. Final Answer:

   Using assignment '=' instead of comparison '===' in if conditions -> Option D

4. Quick Check:

   Use '===' for comparisons, not '=' [OK]

Hint: Use '===' for comparisons, '=' is assignment [OK]

Common Mistakes:

• Confusing '=' with '==' or '==='
• Ignoring that assignment returns a value
• Not validating all possible status codes

5. You want to write a Postman test that checks if the response status is 200 and the JSON body has a 'data' field, but if the status is 404, it should check for an 'error' message. Which code snippet correctly implements this conditional response test?

hard

A. pm.test('Conditional response test', () => {
if (pm.response.code === 200) {
pm.expect(pm.response.json().data).to.exist;
} else if (pm.response.code === 404) {
pm.expect(pm.response.json().error).to.exist;
} else {
pm.expect.fail('Unexpected status code');
}
});

B. pm.test('Conditional response test', () => {
pm.expect(pm.response.code === 200 && pm.response.json().data).to.exist;
pm.expect(pm.response.code === 404 && pm.response.json().error).to.exist;
});

C. pm.test('Conditional response test', () => {
if (pm.response.code = 200) {
pm.expect(pm.response.json().data).to.exist;
} else if (pm.response.code = 404) {
pm.expect(pm.response.json().error).to.exist;
}
});

D. pm.test('Conditional response test', () => {
pm.expect(pm.response.json().data || pm.response.json().error).to.exist;
});

Solution

1. Step 1: Check correct use of comparison operators

   pm.test('Conditional response test', () => { if (pm.response.code === 200) { pm.expect(pm.response.json().data).to.exist; } else if (pm.response.code === 404) { pm.expect(pm.response.json().error).to.exist; } else { pm.expect.fail('Unexpected status code'); } }); uses '===' for comparisons correctly. Using '=' causes assignment instead of comparison.

2. Step 2: Verify conditional logic and assertions

   The code checks 'data' field existence for status 200, 'error' for 404, and explicitly fails for unexpected codes using pm.expect.fail().

3. Step 3: Evaluate other options

   One option incorrectly combines status and field checks in single pm.expect statements, causing failures. Another does not condition on status codes at all.

4. Final Answer:

   pm.test('Conditional response test', () => { if (pm.response.code === 200) { pm.expect(pm.response.json().data).to.exist; } else if (pm.response.code === 404) { pm.expect(pm.response.json().error).to.exist; } else { pm.expect.fail('Unexpected status code'); } }); -> Option A

5. Quick Check:

   Use if-else with '===' and proper assertions [OK]

Hint: Use if-else with '===' and separate assertions [OK]

Common Mistakes:

• Using '=' instead of '===' in conditions
• Combining conditions inside one pm.expect
• Not handling unexpected status codes