Snapshot testing queries in GraphQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to write a GraphQL query that fetches the user's name.

GraphQL

query GetUserName { user { [1] } }

Drag options to blanks, or click blank then click option'

Aname

Bemail

Cid

Dage

Attempts:

3 left

💡 Hint

Common Mistakes

Using email or id instead of name.

The field name fetches the user's name in the query.

2fill in blank

medium

Complete the code to fetch the user's posts with their titles.

GraphQL

query GetUserPosts { user { posts { [1] } } }

Drag options to blanks, or click blank then click option'

Acontent

Btitle

Cdate

Dauthor

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing content or date instead of title.

The title field fetches the title of each post.

3fill in blank

hard

Fix the error in the query to fetch user's email correctly.

GraphQL

query GetUserEmail { user { [1] } }

Drag options to blanks, or click blank then click option'

Aemails

BuserEmail

Cemail

Dcontact

Attempts:

3 left

💡 Hint

Common Mistakes

Using emails or userEmail which do not exist.

The correct field to fetch the user's email is email.

4fill in blank

hard

Fill both blanks to query posts with title and published date.

GraphQL

query GetPosts { posts { [1] [2] } }

Drag options to blanks, or click blank then click option'

Atitle

Bcontent

CpublishedDate

Dauthor

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing content or author instead of publishedDate.

The query fetches title and publishedDate fields for posts.

5fill in blank

hard

Fill all three blanks to query user with uppercase name, email, and posts count.

GraphQL

query GetUserDetails { user { [1] email postsCount: [2] posts { [3] } } }

Drag options to blanks, or click blank then click option'

Aname @upperCase

Bcount

Ctitle

Dname

Attempts:

3 left

💡 Hint

Common Mistakes

Using name @upperCase which is not valid here.

The query fetches name (normal), count as postsCount, and title of posts.

Practice

1. What is the main purpose of snapshot testing in GraphQL queries?

easy

A. To improve the speed of GraphQL queries

B. To generate new GraphQL schemas

C. To detect unexpected changes in query results automatically

D. To optimize database indexing

Solution

1. Step 1: Understand snapshot testing concept

   Snapshot testing captures the output of a query at a point in time to compare later.

2. Step 2: Identify the purpose in GraphQL context

   It helps catch unexpected changes in the query results automatically during tests.

3. Final Answer:

   To detect unexpected changes in query results automatically -> Option C

4. Quick Check:

   Snapshot testing = detect changes automatically [OK]

Hint: Snapshot testing checks if query results change unexpectedly [OK]

Common Mistakes:

• Thinking snapshot testing speeds up queries
• Confusing snapshot testing with schema generation
• Assuming it optimizes database indexes

2. Which of the following is the correct syntax to write a simple GraphQL query for snapshot testing user names and emails?

easy

A. query { users name email }

B. query users { name, email }

C. { users: name, email }

D. query { users { name, email } }

Solution

1. Step 1: Recall GraphQL query syntax

   A valid query starts with 'query' keyword, then braces with fields selected properly.

2. Step 2: Check each option's syntax

   query { users { name, email } } correctly uses 'query { users { name, email } }' with nested braces for fields.

3. Final Answer:

   query { users { name, email } } -> Option D

4. Quick Check:

   Correct GraphQL query syntax = query { users { name, email } } [OK]

Hint: GraphQL queries need nested braces for fields inside objects [OK]

Common Mistakes:

• Missing braces around fields
• Incorrect use of colon or commas
• Omitting 'query' keyword or braces

3. Given this GraphQL query for snapshot testing:
query { posts { id title author { name } } }
What will be the shape of the returned JSON data?

medium

A. {"data":{"posts":[{"id":1,"title":"Hello","author":{"name":"Alice"}}]}}

B. {"posts":[{"id":1,"title":"Hello","author":{"name":"Alice"}}]}

C. {"data":{"posts":{"id":1,"title":"Hello","author":{"name":"Alice"}}}}

D. {"data":{"posts":[{"id":1,"title":"Hello","author":"Alice"}]}}

Solution

1. Step 1: Understand GraphQL response format

   GraphQL responses wrap results inside a 'data' object, with arrays for list fields.

2. Step 2: Analyze the query structure

   'posts' is a list, so its value is an array of objects with 'id', 'title', and nested 'author' object.

3. Final Answer:

   {"data":{"posts":[{"id":1,"title":"Hello","author":{"name":"Alice"}}]}} -> Option A

4. Quick Check:

   GraphQL response = data object with arrays for lists [OK]

Hint: GraphQL responses always wrap data inside a 'data' field [OK]

Common Mistakes:

• Omitting the 'data' wrapper
• Using object instead of array for list fields
• Flattening nested objects incorrectly

4. You wrote this snapshot test query:
query { user { id name email } }
But the test fails with an error: "Cannot query field 'user' on type 'Query'".
What is the most likely cause?

medium

A. The schema does not have a 'user' field on the root Query type

B. The query is missing the 'query' keyword

C. The fields inside 'user' are invalid

D. Snapshot testing does not support nested fields

Solution

1. Step 1: Interpret the error message

   The error says 'user' field is not found on the root Query type in the schema.

2. Step 2: Check query syntax and schema

   The query syntax is valid, so the problem is likely the schema missing 'user' field.

3. Final Answer:

   The schema does not have a 'user' field on the root Query type -> Option A

4. Quick Check:

   Field missing in schema = The schema does not have a 'user' field on the root Query type [OK]

Hint: Check schema fields if query field causes 'Cannot query field' error [OK]

Common Mistakes:

• Assuming missing 'query' keyword causes this error
• Blaming nested fields without schema check
• Thinking snapshot testing limits field nesting

5. You want to create a snapshot test for a GraphQL query that fetches a list of products with their id, name, and price, but only for products priced above $50.
Which query correctly applies this filter for snapshot testing?

hard

A. query { products(filter: { price: { gt: 50 } }) { id name price } }

B. query { products(filter: { price_gt: 50 }) { id name price } }

C. query { products { id name price if price > 50 } }

D. query { products { id name price where price > 50 } }

Solution

1. Step 1: Understand GraphQL filtering syntax

   Filters are usually passed as arguments with field names and operators like 'price_gt' for greater than.

2. Step 2: Evaluate each option's filter usage

   query { products(filter: { price_gt: 50 }) { id name price } } uses 'filter: { price_gt: 50 }' which is a common and correct pattern.

3. Final Answer:

   query { products(filter: { price_gt: 50 }) { id name price } } -> Option B

4. Quick Check:

   Use filter arguments with operator suffixes like _gt [OK]

Hint: Use filter arguments with _gt for greater than in GraphQL [OK]

Common Mistakes:

• Placing conditions inside selection sets
• Using invalid keywords like 'where' or 'if' inside query
• Incorrect nested filter object structure