API test tools overview in Testing Fundamentals - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding API Testing Tools

Which of the following best describes the primary purpose of API testing tools?

A To automate the testing of backend services by sending requests and validating responses

B To create database schemas and manage data migrations

C To monitor server hardware performance during peak loads

D To verify the user interface elements and their responsiveness

💡 Hint

Think about what APIs do and what testing them involves.

API testing tools focus on sending requests to backend services and checking if the responses are correct, without involving the user interface.

❓ Predict Output

intermediate

Output of a Postman Test Script

Consider this Postman test script snippet that checks if the response status is 200:

pm.test("Status code is 200", function () {
    pm.response.to.have.status(200);
});

What will be the test result if the API response status is 404?

Testing Fundamentals

pm.test("Status code is 200", function () {
    pm.response.to.have.status(200);
});

A Test passes because the script only checks for status existence

B Test fails because the response status is not 200

C Test throws a syntax error due to missing semicolon

D Test is skipped because 404 is a valid response

💡 Hint

Check what the assertion is verifying exactly.

The test expects the response status to be exactly 200. If the actual status is 404, the assertion fails and the test fails.

❓ locator

advanced

Choosing the Best Locator for API Endpoint Testing

When configuring an API test in a tool like SoapUI or Postman, which of the following is the best practice for specifying the API endpoint URL?

A Hardcode the full URL including query parameters directly in the test script

B Use relative file paths to locate the API endpoint on the local machine

C Use environment variables or configuration files to store the base URL and append endpoints dynamically

D Embed the API endpoint inside the request body as a string

💡 Hint

Think about flexibility and maintainability in tests.

Using environment variables or config files allows easy updates and reuse of tests across different environments without changing the test scripts.

❓ assertion

advanced

Validating JSON Response Content

Given an API response JSON: {"user":{"id":123,"name":"Alice"}}, which Postman test assertion correctly verifies that the user's name is 'Alice'?

A pm.expect(pm.response.json().user.name).to.eql('Alice');

B pm.expect(pm.response.json().user['id']).to.eql('Alice');

C pm.expect(pm.response.text()).to.include('user.name: Alice');

D pm.expect(pm.response.json().user.name).to.be.undefined;

💡 Hint

Focus on accessing the correct JSON property and comparing its value.

Option A correctly accesses the 'name' property inside 'user' and checks if it equals 'Alice'. Other options either check wrong properties or incorrect values.

❓ framework

expert

Choosing the Right API Testing Framework for Automation

You need to automate API tests for a RESTful service with complex authentication and data-driven scenarios. Which framework choice below best supports this need?

A Use a simple HTTP client library without test assertions or reporting features

B Use manual testing with Postman collections only, without automation

C Use a UI testing framework like Selenium to automate API calls through the browser

D Use a dedicated API testing framework like REST-assured (Java) or pytest with requests (Python) that supports assertions, authentication, and data-driven tests

💡 Hint

Consider automation, authentication, and data-driven testing support.

Frameworks like REST-assured or pytest with requests provide built-in support for assertions, authentication, and data-driven testing, making them suitable for complex API automation.

Practice

1. Which of the following is a popular tool used for manual API testing with a user-friendly interface?

easy

A. Selenium

B. JUnit

C. Postman

D. JMeter

Solution

1. Step 1: Identify tools for API testing

   Postman is widely known as a manual API testing tool with a graphical interface.

2. Step 2: Differentiate from other tools

   JUnit is for unit testing, Selenium for UI testing, and JMeter for performance testing, not primarily manual API testing.

3. Final Answer:

   Postman -> Option C

4. Quick Check:

   Manual API testing tool = Postman [OK]

Hint: Postman = manual API testing with GUI [OK]

Common Mistakes:

• Confusing JUnit as an API testing tool
• Thinking Selenium is for API testing
• Assuming JMeter is mainly for API functional testing

2. Which command-line tool is commonly used to send HTTP requests for API testing?

easy

A. docker

B. npm

C. git

D. curl

Solution

1. Step 1: Identify command-line tools related to HTTP requests

   curl is a command-line tool designed to send HTTP requests and test APIs.

2. Step 2: Exclude unrelated tools

   npm manages Node.js packages, git manages source code, and docker manages containers, none are for HTTP requests.

3. Final Answer:

   curl -> Option D

4. Quick Check:

   Command-line HTTP tool = curl [OK]

Hint: curl sends HTTP requests from terminal [OK]

Common Mistakes:

• Confusing npm with API testing
• Thinking git can send HTTP requests
• Assuming docker is for API calls

3. Consider this REST-assured Java code snippet for API testing:

given().when().get("https://api.example.com/users/1").then().statusCode(200);

What does this test check?

medium

A. The API returns status code 200 for user with ID 1

B. The API returns a list of all users

C. The API creates a new user

D. The API returns status code 404 for user with ID 1

Solution

1. Step 1: Analyze the HTTP method and URL

   The code uses GET on endpoint /users/1, which typically fetches user with ID 1.

2. Step 2: Check the assertion on status code

   The test expects the response status code to be 200, meaning success.

3. Final Answer:

   The API returns status code 200 for user with ID 1 -> Option A

4. Quick Check:

   GET /users/1 expects 200 = The API returns status code 200 for user with ID 1 [OK]

Hint: GET + statusCode(200) means successful fetch [OK]

Common Mistakes:

• Thinking it creates a user (POST needed)
• Assuming it fetches all users (no list endpoint)
• Confusing 404 with 200 status code

4. You wrote this curl command to test an API:

curl -X GET https://api.example.com/data -d '{"id":5}'

What is wrong with this command?

medium

A. GET requests should not have a request body (-d option)

B. The URL is missing the protocol

C. The HTTP method should be POST, not GET

D. The JSON data is missing a closing brace

Solution

1. Step 1: Understand HTTP GET request rules

   GET requests usually do not have a body; sending data with -d is ignored or causes errors.

2. Step 2: Check other parts of the command

   The URL includes protocol https://, JSON is properly closed, and GET is valid method for fetching data.

3. Final Answer:

   GET requests should not have a request body (-d option) -> Option A

4. Quick Check:

   GET with body (-d) is invalid [OK]

Hint: GET requests don't send data in body (-d) [OK]

Common Mistakes:

• Thinking URL lacks protocol
• Assuming POST is required here
• Missing JSON brace (actually present)

5. You want to automate API tests that check multiple endpoints with different HTTP methods and validate JSON responses. Which tool is best suited for this task?

hard

A. Postman manual runner

B. REST-assured

C. curl command line only

D. Browser developer tools

Solution

1. Step 1: Identify automation needs

   Testing multiple endpoints with various HTTP methods and validating JSON requires scripting and assertions.

2. Step 2: Match tool capabilities

   REST-assured is a Java library designed for automated API testing with rich validation support.

3. Step 3: Exclude less suitable tools

   Postman manual runner is not fully automated, curl lacks built-in assertions, and browser tools are for debugging, not automation.

4. Final Answer:

   REST-assured -> Option B

5. Quick Check:

   Automated API testing with assertions = REST-assured [OK]

Hint: REST-assured = automated API tests with assertions [OK]

Common Mistakes:

• Choosing Postman manual runner for automation
• Using curl without assertion support
• Relying on browser tools for automated tests