API Testing: 60 Test Cases & Best Practices

1. Test Cases For API Functional Testing

Functionality is the nucleus of any Application Under Test (AUT), and API is no exception.

Their most canonic and foundational functionality is data retrieval and data sending, and API functional testing should orbit around those 2 arena. Check out the undermentioned functional exam cases and see how you can apply them to your own testing project:

1. Status Code Validation for Valid Requests: Verify that the API consistently returns the expected response status code, such as `` 200 OK, '' for valid and properly formatted requests.
2. Authentication Handling with Invalid Credentials: Test the API 's response when provided with invalid authentication certification, ensuring it systematically returns a `` 401 Unauthorized '' status codification as expected.
3. Graceful Handling of Missing or Invalid Parameters: Verify that the API cover missing or invalid request parameters gracefully and returns clear and user-friendly error messages that aid in troubleshooting.
4. Input Data Validation with Malformed Data: Test the API 's stimulant substantiation by submitting respective descriptor of malformed information, such as invalid email formats, and confirm that it properly rejects and responds to these stimulant.
5. Timeout Handling under Load: Confirm that the API correctly handles timeouts by simulating requests that take longer to treat, ensuring that it stay reactive and does not hang.
6. Pagination Functionality Verification: Test the API 's pagination functionality by requesting specific pages of results and verifying that the responses comprise the expected data and pagination information.
7. Concurrency Testing without Data Corruption: Verify that the API handle coincidental request from multiple users without data corruption or fight, ensuring data integrity.
8. Response Format Adherence (JSON/XML): Ensure that the API consistently returns answer in the specified format (e.g., JSON or XML) and adheres to the specify schema for datum structure.
9. Caching Mechanism Evaluation with Repeated Requests: Evaluate the API 's caching mechanism by make repeated requests and verifying that the cache headers are correctly set and honored.
10. Rate Limiting Assessment: Test the API 's rate limiting by post asking at a rate that exceeds the outlined limits and check for the expected rate-limiting reaction, secure that bound are enforced.
11. HTTP Method Support for CRUD Operations: Verify that the API supports a multifariousness of HTTP methods (GET, POST, PUT, DELETE) for Create, Read, Update, and Delete operation, and that it returns appropriate responses for each.
12. Error Handling Capabilities for Meaningful Messages: Evaluate the API 's error-handling capableness by intentionally causing errors, such as invalid remark or unexpected position, and confirm that it consistently returns meaningful error messages for troubleshooting.
13. Conditional Request Handling (If-Modified-Since, If-None-Match): Test the API 's support for conditional requests using head like If-Modified-Since and If-None-Match, ensuring that responses are handled appropriately.
14. Sorting and Filtering Validation for Resource Listings: Verify that the API correctly sorts and filters resource itemisation based on specified argument, maintain data truth.
15. Handling Long or Complex Data without Data Corruption: Ensure that the API properly handgrip long or complex string, such as URLs or text fields, without truncate or subvert the data.
16. Content Negotiation Support for Multiple Formats: Test the API 's support for contented negotiation by specifying different Accept lintel (e.g., JSON, XML) and verifying that the response format matches the requested format.
17. Resource Not Found Handling (404 Not Found): Confirm that the API consistently returns the appropriate `` 404 Not Found '' response when attempting to approach a non-existent resource.
18. Response Time Measurement for Various Requests: Measure the API 's reaction time for different character of requests to valuate its performance and responsiveness.
19. Handling Large Payloads (File Uploads): Verify that the API can address large payloads, such as file uploads, without encountering error or substantial performance degradation.
20. Compatibility with Client Libraries and SDKs: Evaluate the API 's compatibility with different node library or SDKs to ensure unlined integration with assorted program and programming languages.

→ Check out the top automated functional testing tools on the current grocery

2. Test Cases For API Performance Testing

If the API germinate in your squad receives eminent traffic, it is a good thought to incorporate execution testing into your daily routine. In fact, execution testing should get even before maturation begin since it ply valuable insights into the maximum stress level of the server, which can help the IT Ops squad better allocate and optimize resources usage. Here are some common test cases when doing execution testing of your APIs:

1. Baseline Response Time: Measure the response time of a bare API postulation under normal weather to establish a execution baseline.
2. Stress Testing: Send a orotund number of simultaneous postulation to the API to assess its performance under heavy load.
3. Concurrency Testing: Evaluate how the API handles a specified number of co-occurrent requests without execution degradation.
4. Ramp-up Testing: Gradually increase the figure of request over time to place the API 's breakage point and performance limits.
5. Peak Load Testing: Test the API 's performance at peak usage clip to ensure it can handle maximal expected traffic.
6. Endurance Testing: Continuously send requests to the API for an drawn-out length to assess its stability over time.
7. Scalability Testing: Increase the load gradually and quantify how the API scales by adding more resources (e.g., servers) to maintain performance.
8. Resource Utilization Testing: Monitor CPU, memory, and meshing utilization while conducting performance test to place resource bottlenecks.
9. Response Time Distribution: Analyze the distribution of response times to place outliers and performance issue.
10. Latency Testing: Measure network latency between the client and the API server to ensure low latency for users.
11. Throughput Testing: Determine the maximal number of transaction the API can handle per unit of time while hold acceptable response times.
12. Error Rate Testing: Monitor and record the rate of errors or failed requests during load testing to assess error handling and resilience.
13. Caching Performance: Evaluate the impingement of caching on response times and resource employment.
14. Data Volume Testing: Test the API with varying data volumes (e.g., modest, medium, large load) to assess its performance with different data sizes.
15. Geographical Load Testing: Simulate requests from different geographical position to assess the API 's global performance and response clip.
16. Concurrency with Authentication: Evaluate how the API handles concurrent requests with authentication, including token proof.
17. Database Load Testing: Assess the impact of API requests on the associated database by measuring inquiry reply times.
18. Long-Running Transactions: Test transactions that guide a significant amount of time to dispatch and assess their impingement on overall scheme performance.
19. Rate Limiting Stress Testing: Test how the API handles excessive requests when rate limiting is in place.
20. Failover Testing: Simulate host failure and test the API 's ability to failover to backup servers while maintaining performance.

You May Also Like: Performance Testing vs Load Testing: A Complete Guide

3. Test Cases For API Security Testing

SUSA automates exploratory testing with persona-driven behavior, catching bugs that scripted automation misses.

Finally, also make sure to check the security of your API, since this is the area where sensitive and high-value information is exchanged. APIs experience always be a common target of assaulter look to profit unauthorized access to your systems. Some mutual API security tryout cases are:

1. Authentication Testing: Verify that the API enforces proper authentication for all endpoints.
2. Authorization Testing: Ensure that users can approach only the resources they are pass to access.
3. Token Security: Test the security of hallmark tokens, including token encryption and expiration.
4. Session Management: Check for secure session management and handling of session cookies.
5. SQL Injection: Test forSQL injection vulnerabilityby injecting malicious SQL queries in API parameter.
6. Cross-Site Scripting (XSS): Verify that the API is protected against XSS attacks by inject malicious playscript.
7. Cross-Site Request Forgery (CSRF): Test if the API is vulnerable toCSRF attacksby submitting unauthorized requests.
8. Input Validation: Ensure that the API validates and sanitizes exploiter inputs to keep injection attacks.
9. Rate Limiting: Test the API 's rate modification to prevent abuse and DoS attacks.
10. Sensitive Data Exposure: Verify that sensitive data, such as word or API keys, are not exposed in responses.
11. HTTPS/TLS Testing: Ensure that the API uses secure communication via HTTPS/TLS and checks for certification validity.
12. CORS (Cross-Origin Resource Sharing) Security: Test for correct CORS head to prevent unauthorized cross-origin requests.
13. API Key Security: Assess the protection of API keys and their store.
14. JWT (JSON Web Token) Security: Evaluate the security of JWTs used for authentication and sanction.
15. Authentication Bypass: Attempt to bypass hallmark mechanism and gain unauthorized access.
16. Session Fixation: Test if the API is vulnerable to session regression attacks.
17. Insecure Direct Object References (IDOR): Check for unauthorized admission to resources by manipulating object acknowledgment.
18. Denial of Service (DoS) Testing: Attempt to clog the API and test its resilience against DoS attacks.
19. API Versioning: Verify that the API supports versioning to preclude breaking change from affect existing clients.
20. Security Headers: Check for the presence of security header such as Content Security Policy (CSP), X-Content-Type-Options, etc., in API reply.

Read More:What is Penetration Testing? Definition, Practices, Tools

How To Write Test Cases For API Testing?

When publish a test instance for API testing specifically, & nbsp;

1. Understand the API thoroughly. Read through the API documentation from the API provider. Also see if an & nbsp;API sandboxis useable for quiz, and if there is, ascertain its documentation too.
2. Follow a consistent designation convention for test cases.
3. You can group like test cases together under a mutual feature/scenario
4. Familiarize yourself with the requirement or feature you 're testing before create the test example so that you ’ ll know what information to include
5. Use activeness verb at the start of each test step like “ Click ”, “ Enter ” or “ Validate ”. If needed, you may even create a semantic construction to describe your tryout case. You can check out how it is perform in & nbsp;BDD testing.
6. Include any setup or prerequisites needed beforeaccomplish the test.
7. Ensure that the test cases you included are not only the “ mutual ” scenarios but also the negative scenarios that user don ’ t typically face but do happen in the scheme
8. Use formatting to make your test cases easier to read and follow
9. Make sure to update your test suit regularly

Test Case Template For API Testing

To outdo write your test cases, you should always have atest instance template, which we have prepared in PDF, Doc, and Excel sheet formats for you to download. Simply hit the button below and start noting down your examination cases right away.

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