API API Mocking and Stubbing

Question 1

What is an API mock in the context of software testing?

Accepted Answer

A simulated API that mimics the behavior of a real API with predefined responses

Answer

A real API endpoint that returns live production data

Answer

A testing framework used for validating API response schemas

Answer

A monitoring tool that records API traffic in real time

Question 2

What is the primary difference between a mock and a stub in API testing?

Accepted Answer

A stub returns canned responses without verifying interactions, while a mock also sets and verifies expectations about how it was called

Answer

Stubs are only used for HTTP APIs while mocks support any protocol

Answer

Mocks are simpler than stubs and do not support dynamic configuration

Answer

There is no difference; mock and stub are fully interchangeable terms

Question 3

Which scenario is best suited for using an API mock during development?

Accepted Answer

When the third-party API is unavailable, still under development, or too costly to call repeatedly

Answer

When you want to validate real API performance under heavy concurrent load

Answer

When you need to verify the API's TLS certificate chain is valid

Answer

When testing requires live production data that cannot be replicated offline

Question 4

In test double terminology, what is a 'fake'?

Accepted Answer

A working but simplified implementation that behaves correctly yet is unsuitable for production

Answer

An invalid API response deliberately crafted to trigger error handling

Answer

A recorded HTTP response from a real API that is replayed during tests

Answer

A stub that only responds to GET requests and ignores all others

Question 5

What does 'service virtualization' mean in the context of API testing?

Accepted Answer

Creating simulated replicas of dependent services to enable testing when real services are unavailable

Answer

Running API test suites inside virtual machine environments

Answer

Virtualizing network bandwidth between microservices for performance testing

Answer

Hosting API documentation on a cloud-based virtual server

Question 6

Which of the following is a primary benefit of API mocking during parallel team development?

Accepted Answer

Frontend and backend teams can develop and test independently against an agreed-upon API contract

Answer

Mocks eliminate the need for any integration testing later in the development cycle

Answer

Mocks consistently deliver better runtime performance than real API endpoints

Answer

Mocks automatically generate exhaustive test cases directly from the OpenAPI specification

Question 7

What is a 'spy' in test double terminology?

Accepted Answer

A test double that records calls made to it while still delegating to the real underlying implementation

Answer

A security tool that monitors and logs all network traffic between API endpoints

Answer

A mock configured exclusively to validate security and authorization headers

Answer

A stub that returns different responses depending on the values of incoming request parameters