Snapshot testing queries in GraphQL - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ query_result

intermediate

What is the output of this GraphQL query snapshot?

Given the following GraphQL query and snapshot data, what will be the returned data?

{ user(id: "1") { id name posts { id title } } }

Snapshot data:

{"data": {"user": {"id": "1", "name": "Alice", "posts": [{"id": "101", "title": "GraphQL Basics"}, {"id": "102", "title": "Advanced GraphQL"}]}}}

GraphQL

{ user(id: "1") { id name posts { id title } } }

A {"errors":[{"message":"User not found"}]}

B {"data":{"user":{"id":"1","name":"Alice","posts":[]}}}

C {"data":{"user":null}}

D {"data":{"user":{"id":"1","name":"Alice","posts":[{"id":"101","title":"GraphQL Basics"},{"id":"102","title":"Advanced GraphQL"}]}}}

💡 Hint

Look carefully at the snapshot data for the user and posts fields.

The snapshot shows the user with id "1" named "Alice" and two posts. The query returns exactly this data.

🧠 Conceptual

intermediate

Which statement best describes snapshot testing in GraphQL?

Choose the best description of snapshot testing for GraphQL queries.

A Snapshot testing saves the expected query response and compares future responses to detect changes.

B Snapshot testing automatically fixes errors in GraphQL queries by rewriting them.

C Snapshot testing runs queries against a live database to check performance.

D Snapshot testing generates random data to test GraphQL mutations.

💡 Hint

Think about what snapshot testing compares over time.

Snapshot testing captures the output of a query once and compares future outputs to detect unexpected changes.

📝 Syntax

advanced

Which GraphQL query syntax will cause a syntax error in snapshot testing?

Identify the query that will cause a syntax error when used in snapshot testing.

A { user(id: "1") { id name posts { id title } }

B { user(id: "1") { id name } }

C { user(id: "1") { id name posts { id title } } }

D { user(id: 1) { id name } }

💡 Hint

Check for missing brackets or quotes.

Option A is missing the closing curly brace, causing a syntax error.

❓ optimization

advanced

How can snapshot testing queries be optimized for large nested data?

Which approach best optimizes snapshot testing for queries returning large nested data?

A Disable snapshot testing for nested queries to improve speed.

B Always fetch all nested fields to ensure complete snapshots.

C Limit the query fields to only necessary data to reduce snapshot size.

D Use random data generation to simulate nested data in snapshots.

💡 Hint

Think about minimizing data to keep snapshots manageable.

Limiting fields reduces snapshot size and makes tests faster and easier to maintain.

🔧 Debug

expert

Why does this snapshot test fail despite no schema changes?

A snapshot test for this query fails:

{ user(id: "2") { id name posts { id title } } }

Snapshot data:

{"data":{"user":{"id":"2","name":"Bob","posts":[{"id":"201","title":"Intro"}]}}}

Current response:

{"data":{"user":{"id":"2","name":"Bob","posts":[]}}}

What is the most likely cause?

A The query syntax changed causing posts to be omitted.

B The user has no posts currently, so the snapshot is outdated.

C The GraphQL server schema was updated to remove posts field.

D The snapshot file is corrupted and cannot be read.

💡 Hint

Consider data changes versus schema or syntax changes.

The snapshot test fails because the actual data changed (no posts now), but the snapshot expects posts. This is a data change, not a schema or syntax issue.