API Testing Interview Questions And Answers
How to approach API testing
An API testing process should begin with a clearly defined scope of theprogram as well as a full understanding of how the API is supposed to work.Some questions that testers should consider include: * What endpoints are available for testing? * What response codes are expected for successful requests? * What response codes are expected for unsuccessful requests? * Which error message is expected to appear in the body of an unsuccessful request?Once factors such as these are understood, testers can begin applying varioustesting techniques. Test cases should also be written for the API. These testcases define the conditions or variables under which testers can determinewhether a specific system performs correctly and responds appropriately. Oncethe test cases have been specified, testers can perform them and compare theexpected results to the actual results. The test should analyze responses thatinclude: * reply time, * data quality, * confirmation of authorization, * HTTP status code and * error codes.API testing can analyze multiple endpoints, such as web services, databases orweb user interfaces. Testers should watch for failures or unexpected inputs.Response time should be within an acceptable agreed-upon limit, and the APIshould be secured against potential attacks.Tests should also be constructed to ensure users can’t affect the applicationin unexpected ways, that the API can handle the expected user load and thatthe API can work across multiple browsers and devices.The test should also analyze the results of nonfunctional tests as well,including performance and security.
Types of API tests
Various types of API tests can be performed to ensure the applicationprogramming interface is working appropriately. They range from general tospecific analyses of the software. Here are examples of some of these tests.Validation testing includes a few simple questions that address the wholeproject. The first set of questions concerns the product: Was the correctproduct built? Is the designed API the correct product for the issue itattempts to resolve? Was there any major code bloat — production of code thatis unnecessarily long, slow and wasteful — throughout development that wouldpush the API in an unsustainable direction?The second set of questions focuses on the API’s behavior: Is the correct databeing accessed in the predefined manner? Is too much data being accessed? Isthe API storing the data correctly given the data set’s specific integrity andconfidentiality requirements?The third set of questions looks at the efficiency of the API: Is this API themost efficient and accurate method of performing a task? Can any codebase bealtered or entirely removed to reduce impairments and improve overall service?Functional testing ensures the API performs exactly as it is supposed to. Thistest analyzes specific functions within the codebase to guarantee that the APIfunctions within its expected parameters and can handle errors when theresults are outside the designated parameters.Load testing is used to see how many calls an API can handle. This test isoften performed after a specific unit, or the entire codebase, has beencompleted to determine whether the theoretical solution can also work as apractical solution when acting under a given load.Reliability testing ensures the API can produce consistent results and theconnection between platforms is constant.Security testing is often grouped with penetration testing and fuzz testing inthe greater security auditing process. Security testing incorporates aspectsof both penetration and fuzz testing, but also attempts to validate theencryption methods the API uses as well as the access control design. Securitytesting includes the validation of authorization checks for resource accessand user rights management.Penetration testing builds upon security testing. In this test, the API isattacked by a person with limited knowledge of the API. This enables testersto analyze the attack vector from an outside perspective. The attacks used inpenetration testing can be limited to specific elements of the API or they cantarget the API in its entirety.Fuzz testing forcibly inputs huge amounts of random data — also called noiseor fuzz — into the system, attempting to create negative behavior, such as aforced crash or overflow.
Benefits of API testing
API testing guarantees that connections among platforms are reliable, safe andscalable. Specific benefits include: * API test automation requires less code than automated GUI tests, resulting in faster testing and a lower overall cost. * API testing enables developers to access the app without a UI, helping the tester identify errors earlier in the development lifecycle, rather than waiting for them to become bigger issues. This also saves money because errors can be more efficiently resolved when caught early. * API tests are technology and language independent. Data is exchanged using JSON or XML and it contains HTTP requests and responses. * API tests use extreme conditions and inputs when analyzing applications. This removes vulnerabilities and guards the app from malicious code and breakage. * API tests can be integrated with GUI tests. For example, integration can enable new users to be created within the app before a GUI test is performed.While API testing presents these various benefits, it also produceschallenges. The most common limitations found in API tests are parameterselection, parameter combination and call sequencing. Parameter selectionrequires the parameters sent through API requests to be validated — a processthat can be difficult. However, it is necessary that testers guarantee thatall parameter data meets the validation criteria, such as the use ofappropriate string or numerical data, an assigned value range and conformancewith length restrictions.Parameter combination can be challenging because every combination must betested to see if it holds problems related to specific configurations. Callsequencing is also a challenge because every call must appear in a specificorder to ensure the system works correctly. This quickly becomes a challenge,especially when dealing with multithreaded applications.
API testing tools
When performing an API test, developers can either write their own frameworkor choose from a variety of ready-to-use API testing tools. Designing an APItest framework enbles developers to customize the test; they are not limitedto the capabilities of a specific tool and its plugins. Testers can addwhichever library they consider appropriate for their chosen coding platform,build unique and convenient reporting standards and incorporate complicatedlogic into the tests. However, testers need sophisticated coding skills ifthey choose to design their own framework.Conversely, API testing tools provide user-friendly interfaces with minimalcoding requirements that enable less-experienced developers to feasibly deploythe tests. Unfortunately, the tools are often designed to analyze general APIissues and problems more specific to the tester’s API can go unnoticed.A large variety of API testing tools is available, ranging from paidsubscription tools to open source offerings. Some specific examples of APItesting tools include: * SoapUI. The tool focuses on testing API functionality in SOAP and REST APIs and web services. * Apache JMeter. An open source tool for load and functional API testing. * Apigee. A cloud API testing tool from Google that focuses on API performance testing. * REST Assured. An open source, Java-specific language that facilitates and eases the testing of REST APIs. * Swagger UI. An open source tool that creates a webpage that documents APIs used. * Postman. A Google chrome app used for verifying and automating API testing. * Katalon. An open source application that helps with UI automated testing.
Examples of API tests
While the use cases of API testing are endless, here are two examples of teststhat can be performed to guarantee that the API is producing the appropriateresults.When a user opens a social media app — such as Twitter or Instagram — theyare asked to log in. This can be done independently — through the app itself– or through Google or Facebook. This implies the social media app has anexisting agreement with Google and Facebook to access some level of userinformation already supplied to these two sources. An API test must then beconducted to ensure that the social media app can collaborate with Google andFacebook to pull the necessary information that will grant the user access tothe app using login information from the other sources.Another example is travel booking systems, such as Expedia or Kayak. Usersexpect all the cheapest flight options for specific dates to be available anddisplayed to them upon request when using a travel booking system. Thisrequires the app to communicate with all the airlines to find the best flightoptions. This is done through APIs. As a result, API tests must be performedto ensure the travel booking system is successfully communicating with theother companies and presenting the correct results to users in an appropriatetimeframe. Furthermore, if the user then chooses to book a flight and paysusing a third-party payment service, such as PayPal, then API tests must beperformed to guarantee the payment service and travel booking systems caneffectively communicate, process the payment and keep the user’s sensitivedata safe throughout the process.
Best practices for API testing
API testing best practices include: * When defining test cases, group them by category. * Include the selected parameters in the test case itself. * Develop test cases for every potential API input combination to ensure complete test coverage. * Reuse and repeat test cases to monitor the API throughout production. * Use both manual and automated tests to produce better, more trustworthy results. * When testing the API, note what happens consistently and what does not. * API load tests should be used to test the stress on the system. * APIs should be tested for failures. Tests should be repeated until it produces a failed output. The API should be tested so that it fails consistently to identify the problems. * Call sequencing should be performed with a solid plan. * Testing can be made easier by prioritizing the API function calls. * Use a good level of documentation that is easy to understand and automate the documentation creation process. * Keep each test cases self-contained and separate from dependencies, if possible.API Testing Interview QuestionsIf you’re looking for API Testing Interview Questions for Experienced orFreshers, you are at the right place. There are a lot of opportunities frommany reputed companies in the world. According to research API Testing has amarket share of about 16.7%. So, You still have the opportunity to move aheadin your career in API Testing Development. Mindmajix offers Advanced APITesting Interview Questions 2021 that helps you in cracking your interview &acquire a dream career as API Testing Developer.> If you would like to Enrich your career with a API Testing certified> professional, then visit Mindmajix – A Global online training platform: “API> Testing Training” Course. This course will help you to achieve excellence in> this domain.
API Testing Interview Questions And Answers:
Types of API Testing:Testing Type | Description —|— Unit testing | Individual operation functionality testing. Functional testing | Block of unit test results tested together. Load testing | Analyzing performance and functional ability when the load isapplied. Runtime error detection | Manual and automated executions to detect any sortof errors or data leaks. Security testing | To verify the ability to safeguard access and data. Web UI testing | GUI test to identify proper executions of any transactions. Interoperability testing | Validate performance with InteroperabilityProfiles.
Q3. What is the procedure to perform API testing and what exactly needs to
be checked?Ans: During the API testing process, a request is raised to the API with theknown data. This way you can analyze the validation response. Basically,things that must be checked during performing API testing are: 1. Accuracy of data 2. Schema validation 3. HTTP status codes 4. Data type, validations, order, and completeness 5. Authorization checks 6. Implementation of response timeout 7. Error codes in case API returns, and 8. Non-functional testing like performance and security testing
Q7. Name the common protocols used in API testing.
Ans: Many protocols are there that can be used in API testing. These are asfollows:JMS, REST, HTTP, UDDI, and SOAP
Q8. Name different tools used for API testing.
Ans: There are many testing tools available that can be used for API testing.A few of them are:Postman, SoapUi Pro, Curl, and Alert site API monitoring
Q10. What’s the procedure to test API’s?
Ans: For testing API’s one must follow the below-mentioned steps: 1. Make a selection of the suite you like to add the API test case to 2. Now choose the test development mode 3. Next demands the development of test cases for the required API methods 4. After this, you need to configure the control parameters of the application and then test conditions 5. Once done with all the previous steps, configure method validation 6. Now is the time for execution of the API test 7. After this, you can check test reports and filter API test cases 8. Last but not least, sequence all API test cases. That’s it!
Q.7 How to perform API testing?
Ans: API testing is a type of integration testing used to test API to validatethe functionality, performance, and security of the application.API testing should perform the following testing methods: * Discovery testing – This testing manually executes the set of calls documented in the API. * Usability testing – It verifies whether the API is functional, user-friendly, and does API integrates with another platform or not. * Automated testing – It comes while creating a set of scripts or a tool to execute API regularly. * Security testing – It recommends what authentication type is needed and also checks sensitive data encryption. * Documentation – It’s the final phase for a deliverable. The team makes sure the documentation provides enough data to interact with the API.