Mocking resolvers in GraphQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a mocking resolver in GraphQL?

A mocking resolver is a fake function that returns sample data instead of real data, used to test or develop GraphQL APIs without a real backend.

beginner

Why use mocking resolvers during GraphQL API development?

They let you build and test the API schema quickly without needing a real database or backend, helping frontend and backend teams work in parallel.

intermediate

How do you define a simple mocking resolver for a 'User' type with a 'name' field?

You write a resolver function that returns a fixed or random name string when the 'name' field is requested, for example: <br>{ User: { name: () => 'Alice' } }

intermediate

What is the benefit of using libraries like Apollo Server's mocking feature?

They automatically generate fake data for your schema types, saving time and reducing manual work when mocking resolvers.

advanced

Can mocking resolvers simulate errors or delays? Why is this useful?

Yes, mocking resolvers can simulate errors or delays to test how your app handles failures or slow responses, improving robustness.

What does a mocking resolver return in GraphQL?

A Real data from a database

B Nothing

C Sample or fake data

D An error always

Mocking resolvers return sample or fake data to simulate real responses.

Which of these is a reason to use mocking resolvers?

A To encrypt data

B To slow down API responses

C To delete real data

D To speed up frontend development

Mocking resolvers help frontend developers work without waiting for backend completion.

How can you simulate a delay in a mocking resolver?

A By using setTimeout or async delay before returning data

B By returning data immediately

C By throwing an error

D By returning null

Using a delay function like setTimeout simulates slow responses.

Which GraphQL server library has built-in mocking support?

A Apollo Server

B Express

C React

D Vue

Apollo Server includes features to easily mock GraphQL schemas.

What is a key limitation of mocking resolvers?

A They cannot return any data

B They do not connect to real databases

C They always cause errors

D They slow down the server

Mocking resolvers do not fetch real data, so they can't test real backend logic.

Explain what mocking resolvers are and why they are useful in GraphQL development.

Think about how you can test an API without a real database.

Describe how you would create a mocking resolver for a GraphQL type with multiple fields.

Consider how each field needs its own fake data function.