GraphQL body in Postman - Test Execution Trace

Test Overview

This test sends a GraphQL query in the request body using Postman. It verifies that the response contains the expected data field with correct values.

Test Code - Postman Test Script

Postman

pm.test("GraphQL response contains user data", function () {
    const jsonData = pm.response.json();
    pm.expect(jsonData.data).to.have.property('user');
    pm.expect(jsonData.data.user).to.have.property('id').that.is.a('string');
    pm.expect(jsonData.data.user).to.have.property('name').that.is.a('string');
});

Execution Trace - 8 Steps

Step	Action	System State	Assertion	Result
1	Test starts	Postman is ready with GraphQL request body set	—	PASS
2	Send POST request with GraphQL query in body	Request sent to GraphQL endpoint with body containing query { user { id name } }	—	PASS
3	Receive response from server	Response received with JSON body containing data.user object	—	PASS
4	Parse response JSON	Response body parsed into jsonData object	—	PASS
5	Check if 'data' property exists	jsonData contains 'data' key	pm.expect(jsonData.data).to.have.property('user')	PASS
6	Check if 'user' object has 'id' property of type string	jsonData.data.user has 'id' key with string value	pm.expect(jsonData.data.user).to.have.property('id').that.is.a('string')	PASS
7	Check if 'user' object has 'name' property of type string	jsonData.data.user has 'name' key with string value	pm.expect(jsonData.data.user).to.have.property('name').that.is.a('string')	PASS
8	Test ends with all assertions passed	All expected fields verified in response	—	PASS

Failure Scenario

Failing Condition: Response JSON does not contain 'data.user' or 'id'/'name' fields are missing or not strings

Execution Trace Quiz - 3 Questions

What does the test verify first in the GraphQL response?

A That the 'data' object contains a 'user' property

B That the HTTP status code is 200

C That the response time is less than 1 second

D That the 'errors' field is empty

Key Result

Always verify the structure and data types of the GraphQL response fields to ensure the API returns the expected data format.

Practice

1. What is the main purpose of the query field in a GraphQL body when testing with Postman?

easy

A. To list all available API endpoints

B. To define the HTTP headers for the request

C. To set the URL of the GraphQL endpoint

D. To specify the exact data you want to fetch or mutate from the API

Solution

1. Step 1: Understand the role of the query field

   The query field contains the GraphQL query or mutation string that tells the API exactly what data to return or change.

2. Step 2: Differentiate from other request parts

   Headers and URLs are set elsewhere in Postman; the query field is specifically for the GraphQL operation.

3. Final Answer:

   To specify the exact data you want to fetch or mutate from the API -> Option D

4. Quick Check:

   GraphQL query = data request [OK]

Hint: Remember: query means what data you want [OK]

Common Mistakes:

• Confusing query with HTTP headers
• Trying to put URL or endpoint inside query
• Leaving query empty or missing

2. Which of the following is the correct minimal structure of a GraphQL body in Postman?

easy

A. { "query": "{ user { id name } }" }

B. { "url": "https://api.example.com/graphql" }

C. { "headers": { "Content-Type": "application/json" } }

D. { "variables": { "id": 1 } }

Solution

1. Step 1: Identify the required fields in a GraphQL body

   The minimal GraphQL body must have a query field with a valid query string.

2. Step 2: Check each option

   { "query": "{ user { id name } }" } correctly shows a JSON object with a query string. The structures with "url" and "headers" are for other parts of the Postman request, not the body. { "variables": { "id": 1 } } only has variables without a query, which is invalid.

3. Final Answer:

   { "query": "{ user { id name } }" } -> Option A

4. Quick Check:

   GraphQL body needs query string [OK]

Hint: GraphQL body always needs a query string [OK]

Common Mistakes:

• Putting URL or headers inside the GraphQL body
• Sending variables without a query
• Using invalid JSON format

3. Given this GraphQL body in Postman:

{
  "query": "query getUser($id: ID!) { user(id: $id) { name email } }",
  "variables": { "id": "123" }
}

What data will the API return if user 123 exists?

medium

A. Only the user's ID

B. The user's name and email fields

C. An error because variables are not allowed

D. All users' names and emails

Solution

1. Step 1: Understand the query and variables

   The query requests name and email of a user with a specific id passed as a variable.

2. Step 2: Interpret the expected response

   Since id is set to "123", the API will return the name and email of user 123 if they exist.

3. Final Answer:

   The user's name and email fields -> Option B

4. Quick Check:

   Variables filter data = user 123 info [OK]

Hint: Variables customize queries to fetch specific data [OK]

Common Mistakes:

• Ignoring variables and expecting all users
• Thinking variables cause errors in GraphQL
• Expecting ID field in response without requesting it

4. You send this GraphQL body in Postman:

{
  "query": "query getUser($id: ID!) { user(id: $id) { name email } }"
}

The API returns an error about missing variables. What is the fix?

medium

A. Add a variables field with the required id value

B. Remove the $id variable from the query

C. Change the query to a mutation

D. Add HTTP headers for authentication

Solution

1. Step 1: Identify the cause of the error

   The query requires a variable $id but no variables field was sent, so the API complains about missing input.

2. Step 2: Fix by adding variables

   Include a variables JSON object with the id value, e.g., { "id": "123" }, to satisfy the query requirement.

3. Final Answer:

   Add a variables field with the required id value -> Option A

4. Quick Check:

   Variables must match query parameters [OK]

Hint: Always send variables if query requires them [OK]

Common Mistakes:

• Forgetting to send variables when query uses them
• Trying to remove variables from query without adjusting logic
• Assuming authentication fixes variable errors

5. You want to test a GraphQL mutation to update a user's email using variables in Postman. Which GraphQL body correctly uses variables for this mutation?

hard

A. { "query": "mutation updateUser { updateUser(id: $id, email: $email) { id email } }", "variables": { "id": 456, "email": "[e-mail]" } }

B. { "query": "mutation { updateUser(id: 456, email: \"[e-mail]\") { id email } }" }

C. { "query": "mutation updateUser($id: ID!, $email: String!) { updateUser(id: $id, email: $email) { id email } }", "variables": { "id": "456", "email": "[e-mail]" } }

D. { "query": "mutation updateUser($id, $email) { updateUser(id: $id, email: $email) { id email } }", "variables": { "id": "456", "email": "[e-mail]" } }

Solution

1. Step 1: Check variable declarations in mutation

   Variables must be declared with types and exclamation marks for required fields, e.g., $id: ID!, $email: String!.

2. Step 2: Verify variables usage and JSON format

   { "query": "mutation updateUser($id: ID!, $email: String!) { updateUser(id: $id, email: $email) { id email } }", "variables": { "id": "456", "email": "[e-mail]" } } correctly declares variables with types and passes matching variables in JSON. { "query": "mutation { updateUser(id: 456, email: \"[e-mail]\") { id email } }" } hardcodes values without variables. { "query": "mutation updateUser { updateUser(id: $id, email: $email) { id email } }", "variables": { "id": 456, "email": "[e-mail]" } } misses variable types. { "query": "mutation updateUser($id, $email) { updateUser(id: $id, email: $email) { id email } }", "variables": { "id": "456", "email": "[e-mail]" } } misses exclamation marks in variable types.

3. Final Answer:

   { "query": "mutation updateUser($id: ID!, $email: String!) { updateUser(id: $id, email: $email) { id email } }", "variables": { "id": "456", "email": "[e-mail]" } } -> Option C

4. Quick Check:

   Declare variables with types and pass matching values [OK]

Hint: Declare variables with types and pass matching JSON values [OK]

Common Mistakes:

• Omitting variable types or exclamation marks
• Using variables without declaring them
• Hardcoding values instead of using variables