Test Cases For API Testing

API testing mainly focuses on understanding what APIs are and why testing them is crucial for Software application development. This section sets the stage for the rest of the document by outlining the importance of API testing ensuring robust and reliable software In this article we explain Test Cases For API Testing with related examples.

What is API Testing?

API testing involves testing application interfaces directly and as part of integration testing to determine if they meet functionality, reliability performance, and security expectations. API testing is concerned with the business logic layer of the software architecture, as opposed to UI testing, which is more concerned with the appearance and feel of the program.

Test Cases For API Testing For Each Category

Here we cover categories of API testing such as functional testing, load testing, security testing, and more. Here we provide examples of test cases that can be created for each category to ensure comprehensive API testing.

Functional Testing

• Verify that the API returns the correct response for valid input
• Check that the API handles invalid input correctly.

Loading Testing

• Test the APIs performance under heavy load conditions
• Measure response times during peak usage.

Security Testing

• Ensure the API is protected against unauthorized access.
• Verify the data transmission is encrypted.

Generic Test Cases for API Testing

Here are some generic test cases for API testing:

• Input Validation Tests: Ensure the API handles valid inputs correctly.
• Authentication and Authorization Tests: Verify that authentication mechanisms work as expected (e.g., tokens, API keys).
• HTTP Method Tests: Test each supported HTTP method (GET, POST, PUT, DELETE) to verify they perform the expected actions.
• Response Validation Tests: Validate the structure and content of API responses (e.g., JSON schema validation).
• JSON API: Send requests and verify the JSON response format matches the expected schema.
• XML API: Similarly, validate XML responses against their schema.
• XML Schema Validation: Send requests and validate XML responses against their defined XML schema.
• JSON Schema Validation: Validate JSON responses against their JSON schema to ensure correct structure and data types.
• Validate Response Headers: Verify that the API response includes appropriate headers (e.g., Content-Type, Cache-Control) with correct values.
• End-to-End CRUD Flow: Validate the complete CRUD operations (Create, Read, Update, Delete) for application APIs to ensure data integrity and functionality.
• Database Integrity Test Cases: Verify that API operations maintain database integrity, such as checking for correct data insertion, updates, and deletions.

How To Write Test Cases For API Testing

Here we provide step by step guide on how to write effective test cases for API testing. It includes tips on understanding API requirements defining test objects and appropriate tools for testing manually.

Understand the API Requirements

• Study the API documentation.
• Identify the input parameters and expected outputs.

Define Test Objectives

• Determine what needs to be tested.
• Set clear and measurable goals.

Use Appropriate Tools

• Select tools like Postman, SoapUI or JUnit for testing.
• Write test cases where possible.

Test Case Template For API Testing

Providing a standardized templates helps maintain consistency and ensures all necessary details are covered in each test case. The template should include sections for the test case ID, description, preconditions, test steps, expected results and actual results.

Example:

Example: Here we provide a example for verify login with missing password for your reference.

Test Case ID: TC Login 01

Description: Verify that the login fails when the password is missing.

Preconditions: The User must be registered.

Test Steps:

1. Send a POST requests to the login API endpoint /login with a valid username and password.

{
  "username": "[email protected]"
}

Expected Results:

• The API should return a status code of 400 bad Request.
• The response body should contain an error message including indicating that the password is required.

Verify Login with Empty Request Body

1. Send a POST request to the login API endpoint /login with an empty request body.

{ }

Expected Results:

• The API should return a status code of 400 Bad Request.
• The response body should contain an error message indicating that the username and password are required.

Verify Response Time for Login API

1. Send a POST request to the login API endpoint /login with valid credentials.

{
  "username": "[email protected]",
  "password": "test"
}

Expected Results:

• The API should return a status code of 200 OK.
• The response time should be within the acceptable limit (e.g., less than 2 seconds).

Verify Login with SQL Injection

Test Steps:

Send a POST request to the login API endpoint /login with an SQL injection payload in the username or password field.

{
  "username": "[email protected]",
  "password": "test"
}

Expected Results:

• The API should return a status code of 401 Unauthorized or 400 Bad Request.
• The response body should contain an error message indicating invalid credentials or an invalid request.
• The database should remain unaffected by the SQL injection attempt.

Conclusion

In API testing, creating robust test cases ensures that APIs function correctly under various conditions, enhancing software reliability. Test cases cover functional, security, and performance aspects, validating inputs, responses, and system integrations. By systematically testing API endpoints, developers ensure that applications interact seamlessly, handle errors gracefully, and maintain data integrity, thereby delivering a secure and efficient user experience.

1. How do I set up API testing in Spring Testing?

Use tools like RestAssured or MockMVC for testing.

2. What are common challenges in API testing with Spring Boot?

Managing test data and handling asynchronous operations.

3. What is Manual Testing?

Manual testing is the process of manually checking software for defects.

4. Why is Manual Testing Important?

Manual testing is important because it helps identify bugs and issues in the software that automated tests might miss.

5. What are the Types of Manual Testing?

Functional Testing, Integration Testing, System Testing, User Acceptance Testing, Regression Testing.

6. What are the Advantages of Manual Testing?

Flexibility to test different scenarios, Ability to provide user experience feedback, No need for programming skills.

7. What Tools are Used in Manual Testing?

Test management tools like JIRA, TestRail. Bug tracking tools like Bugzilla, Mantis. Documentation tools like Excel, Word.