Integration tests with test server in GraphQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start the test server before running tests.

GraphQL

beforeAll(async () => { await server.[1](); });

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

Astart

Bstop

Crestart

Dinit

Attempts:

3 left

💡 Hint

Common Mistakes

Using stop instead of start will shut down the server before tests.

The start method launches the test server so tests can run against it.

2fill in blank

medium

Complete the code to send a GraphQL query to the test server.

GraphQL

const response = await server.executeOperation({ query: [1] });

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

Amutation

BGET_USERS_QUERY

Csubscription

DDELETE_USER_MUTATION

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a mutation or subscription instead of a query.

You need to pass the GraphQL query string or document. GET_USERS_QUERY is the correct query here.

3fill in blank

hard

Fix the error in the test assertion to check the response status code.

GraphQL

expect(response.[1]).toBe(200);

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

AresponseCode

Bcode

CstatusCode

Dstatus

Attempts:

3 left

💡 Hint

Common Mistakes

Using statusCode or code which are not standard in this context.

The correct property for HTTP status in the response is status.

4fill in blank

hard

Fill both blanks to correctly close the test server after all tests.

GraphQL

afterAll(async () => { await server.[1](); await server.[2](); });

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

Astop

Bclose

Cstart

Drestart

Attempts:

3 left

💡 Hint

Common Mistakes

Using start or restart instead of stop or close.

First, stop the server, then close any open connections.

5fill in blank

hard

Fill all three blanks to write a test that sends a mutation and checks the response data.

GraphQL

test('adds a user', async () => {
  const response = await server.executeOperation({
    query: [1],
    variables: { name: [2] }
  });
  expect(response.data.[3]).toBeDefined();
});

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

AADD_USER_MUTATION

B'Alice'

CaddUser

DGET_USER_QUERY

Attempts:

3 left

💡 Hint

Common Mistakes

Using a query instead of mutation, missing quotes around name, or wrong response field.

The mutation is ADD_USER_MUTATION, the variable name is the string 'Alice', and the response field is addUser.

Practice

1. What is the main purpose of using a test server in GraphQL integration tests?

easy

A. To speed up the production server

B. To run queries and mutations safely without affecting real data

C. To replace the database permanently

D. To generate random data automatically

Solution

1. Step 1: Understand the role of a test server

   A test server is a safe environment that mimics the real server but does not affect actual data.

2. Step 2: Identify the purpose in integration tests

   Integration tests use the test server to check if queries and mutations work together correctly without risk.

3. Final Answer:

   To run queries and mutations safely without affecting real data -> Option B

4. Quick Check:

   Test server = safe testing environment [OK]

Hint: Test server isolates tests from real data changes [OK]

Common Mistakes:

• Thinking test server speeds up production
• Confusing test server with permanent database replacement
• Assuming test server auto-generates data

2. Which of the following is the correct way to start a test server for GraphQL integration tests using Apollo Server?

easy

A. const server = ApolloServer(); server.startServer();

B. const server = ApolloServer(typeDefs, resolvers); server.run();

C. const server = new ApolloServer({ typeDefs, resolvers }); await server.listen();

D. const server = new ApolloServer({ typeDefs, resolvers }); await server.start();

Solution

1. Step 1: Recall Apollo Server setup

   Apollo Server requires creating an instance with typeDefs and resolvers, then calling start() before listen().

2. Step 2: Identify correct method to start server

   The correct method to start the server is await server.start(); before running listen().

3. Final Answer:

   const server = new ApolloServer({ typeDefs, resolvers }); await server.start(); -> Option D

4. Quick Check:

   Use server.start() before listen() [OK]

Hint: Remember to call await server.start() before listen() [OK]

Common Mistakes:

• Calling listen() without starting server
• Using incorrect constructor syntax
• Assuming server.run() or startServer() exist

3. Given this test code snippet for a GraphQL query on a test server:

const result = await server.executeOperation({ query: `query { user(id: 1) { name } }` }); console.log(result.data.user.name);

What will be printed if the user with id 1 has the name "Alice"?

medium

A. undefined

B. null

C. "Alice"

D. Error: user not found

Solution

1. Step 1: Understand executeOperation result

   executeOperation returns an object with data containing the query result if successful.

2. Step 2: Check the query and expected data

   The query requests user with id 1 and its name. If user exists with name "Alice", result.data.user.name will be "Alice".

3. Final Answer:

   "Alice" -> Option C

4. Quick Check:

   Query result matches user name "Alice" [OK]

Hint: executeOperation returns data object with query results [OK]

Common Mistakes:

• Expecting undefined if user exists
• Confusing null with undefined
• Assuming error thrown instead of null result

4. You wrote this test code but it throws an error:

const result = await server.executeOperation({ query: `mutation { addUser(name: "Bob") { id } }` });

What is the most likely cause?

medium

A. The mutation name is incorrect or not defined in schema

B. The query should be a GET request, not mutation

C. executeOperation cannot run mutations

D. Missing await keyword before server.executeOperation

Solution

1. Step 1: Check mutation usage in test

   executeOperation supports mutations, so that is not the issue.

2. Step 2: Verify mutation name and schema

   If mutation name addUser is not defined in the schema, the server throws an error.

3. Final Answer:

   The mutation name is incorrect or not defined in schema -> Option A

4. Quick Check:

   Mutation must exist in schema to run [OK]

Hint: Check mutation name matches schema exactly [OK]

Common Mistakes:

• Thinking executeOperation can't run mutations
• Forgetting to await executeOperation
• Confusing query and mutation types

5. You want to write an integration test that checks if a mutation correctly adds a user and then a query fetches that user. Which sequence correctly tests this on a GraphQL test server?

hard

A. Run mutation with executeOperation, then run query with executeOperation, check query result matches mutation data

B. Run query first, then mutation, then check mutation result

C. Run mutation and query in parallel without waiting, then check results

D. Only run mutation; query testing is unnecessary in integration tests

Solution

1. Step 1: Understand integration test flow

   Integration tests verify that mutations affect data and queries reflect those changes.

2. Step 2: Correct test sequence

   First run mutation to add user, then query to fetch user, then compare results to confirm correctness.

3. Final Answer:

   Run mutation with executeOperation, then run query with executeOperation, check query result matches mutation data -> Option A

4. Quick Check:

   Mutation then query to verify changes [OK]

Hint: Test mutation first, then query to confirm data change [OK]

Common Mistakes:

• Running query before mutation
• Running mutation and query in parallel without order
• Skipping query test after mutation