What is API Testing? API Testing Tutorial Guide for Beginners

What Is An API?

API or Application Programming interface testing can be a standout amongst the most demanding parts of programming and QA testing as they are frequently found on conventions and norms that we regularly do not experience in other different kinds of testing.

While engineers will in general test just the fundamental usefulness, they take a shot at, the analyzers who are responsible for testing the usefulness, the execution and the security of APIs, and finding how all the segments cooperate from start to finish.

What Is API Testing?

An Application Programming Interface (API) at its center is a formal determination that goes about as an ensured contract between two separate bits of programming Present day PC frameworks are commonly planned to utilize the 'layered design approach” This implies the center usefulness of the framework is contained inside the "business rationale" layer as a progression of discrete yet associated business parts. They are in charge of taking data from the different (UIs), performing computations and exchanges on the database layer and afterward displaying the outcomes back to the UI.

Notwithstanding, notwithstanding speaking with individuals by means of the UI layer, PCs frameworks must almost certainly discuss straightforwardly with one another. For instance, your versatile ride-sharing application should speak with the mapping administration, the traffic and climate administrations and other specific applications utilized by the drivers giving the rides. In the cutting edge, interconnected world, we underestimate that all these distinctive frameworks can address each other flawlessly, as a general rule that would not be conceivable without APIs.

API Testing Types

There are many different ways of API testing that can be undertaken. Some of them are mentioned below:

• Integration Testing - ensures that any new changes or increments to the API don't cause issues or bugs in different modules anyplace else in the framework
• Load Testing - guarantees the production setup is equipped for taking care of the expected normal number of synchronous clients getting to the framework.
• Regression Testing - decides if any new changes cause negative impacts in already effective tests for existing usefulness.
• Security Testing - endeavors to abuse potential vulnerabilities in a framework or the fundamental structure.
• User Interface Testing - ensures each part of the UI capacities obviously. Each experiment conceivable is then endeavored to utilize the GUI to guarantee it is effective.
• Functional Testing - takes the framework prerequisites and client case situation and examines each utilization case to make certain the framework is fit for taking care of every single vital situation.
• Stress Testing - is similar to Load testing in the sense that it might take regular cases and run numerous concurrent instances of the case in the meantime. Stress testing makes the test one stride more remote than Load testing since it keeps on pushing extra synchronous clients through the framework until the framework achieves a failure / disappointment point. Stress tests can be performed on both a framework wide dimension just as on quite certain parts of a framework.

There are additional tests that are present and utilized for API Testing purposes but the most common tests on APIs that are performed are Load Testing and Stress Testing and they are industry-wide standard tests that are the most commonly done.

Advantages Of API Testing

Upon comparison between  Graphical User Interface (GUI) testing and Application Programming Interface (API) testing, it gives a few key focal points, every one of which can improve the inclusion of your test cycle, monitor assets, and result in quicker, increasingly effective discharges. In light of your undertaking course of events, mix prerequisites, and wanted usefulness, API testing is typically an advantageous methodology when testing your application in-house or with a seaward QA group. Four key favorable circumstances of API testing include:

A). Core Functionality Test

The primary real preferred standpoint of API testing is access to the application without a UI. Testing the center, code-level usefulness of the application gives an early assessment of its general form quality before running GUI tests. This helps uncover the little mistakes that can putrefy and increase issues amid GUI testing. Center access likewise empowers testing pair with advancement, cultivating correspondence and improved coordinated effort between the two groups. This is particularly favorable on the off chance that you are playing out your API testing with a seaward QA group.

B). Time Efficiency

Programming interface testing is far less tedious than utilitarian GUI testing. In GUI testing, website page components must be surveyed, which backs the testing procedure off monstrously. To get a thought of the measure of time APIs can spare when testing the center usefulness of your application, think about the accompanying genuine precedent:

Read: Difference Between Software Development Life Cycle and Software Testing Life Cycle

• 3,000 API tests in 50 minutes (in parallel execution)
• 3,000 GUI tests in 30 hours (in parallel execution)

In spite of the fact that this measurement is a normal determined by our group of specialists, you can anticipate practically identical time reserve funds on the off chance that you utilize an API for a comparative test schedule. Programming interface test mechanization requires less code and in this manner gives better, quicker test inclusion than computerized GUI tests. The final product of quicker testing is a diminished generally speaking testing cost.

C). Independent Of Language

In an API test, information is traded utilizing XML or JSON. These exchange modes are totally language-autonomous, enabling you to choose any center language while seeking after mechanized testing administrations for your application.

D). Simple Integration And Seamless Incorporation With Gui

With API testing, exceptionally integrable tests are conceivable. This is particularly useful on the off chance that you intend to perform practical GUI tests following your API testing. For instance, simple reconciliation would take into consideration the making of new clients inside the application before the beginning of a GUI test.

What Exactly Needs To Be Verified In Api Testing?

The parameters that need to be tested and verified in API Testing are:

• Input Parameters
• Expected Resulting Outputs
• Maximum Time to receive a Response
• Parsing Inputs
• Error Handling
• Proper Response Formatting

Each test parameter ought to be incorporated into a testing content and pursue effectively each new form of the code. Ideally, each test ought to likewise be booked as a major aspect of a load test or a stress test to check that the API can deal with a concurrent load of every single diverse sort of tests immediately without issue.

Tools Used For API Testing

I will give a rundown of the top API testing software and tools covering both open-source and business arrangements that testing groups can choose to suit their requirements.

1). Soap UI

SoapUI is a headless useful testing device committed to API testing, enabling clients to test REST and SOAP APIs and Web Services effectively. Using the free bundle of SOAPUI, clients can get the full source code and construct their favored highlights.

2). Katalon Studio

Katalon Studio is a free test robotization device for API, Web, and Mobile applications. It is rising as the main device for API/Web administrations testing and situating itself as a thorough start to finish mechanization answer for the two designers and analyzers. Katalon Studio underpins both SOAP and REST demands with different sorts of directions and parameterization functionalities. Additionally, the ability to join UI and API/Web administrations for various situations (Windows, Mac OS, and Linux) has been viewed as a remarkable preferred standpoint of Katalon Studio among the top API apparatuses.

3). Postman

Being initially a Chrome program module, Postman presently expands their answer with the local form for both Mac and Windows. Postman is a decent decision for API testing for the individuals who would prefer not to manage to code in an incorporated improvement condition utilizing a similar language as the engineers.

Read: Top 30 Manual Testing Interview Questions & Answers for Fresher

4). Tricentis Tosca

Tricentis Tosca is a ceaseless testing stage for Agile and DevOps. Advantages of Tricentis Tosca incorporates underpins for many cluster of conventions like HTTP(s) JMS, AMQP, Rabbit MQ, TIBCO EMS, SOAP, REST, IBM MQ, NET TCP. It likewise incorporates into the Agile and DevOps Cycle. Besides it augments reuse and practicality with model-based test robotization and as an or more point API tests can be utilized crosswise.

5). Apigee

Apigee is a cross-cloud API testing instrument, enabling clients to gauge and test API execution, supports and manufacture API utilizing different editors like Swagger. It is multi-step and fueled by Javascript and permits the structure screen, sends, and scale APIs Challenges In API Testing

Testing groups face a few special difficulties when testing Application Programming Interface (API) usage. Programming interface testing is a piece of the combinations testing procedure and concerns the correspondence between two frameworks. Some of the challenges faced during the API Testing process are:

1). Beginning Setup Of API Testing

Manual testing affirms in the case of something works. Mechanized testing is vital with APIs to measure how well they perform under strain. Getting the testing foundation fully operational is frequently a standout amongst the most testing pieces of the process– not on the grounds that it is especially troublesome, but since it very well may be a considerable inspiration executioner. When you figure out how to inspire your group to overcome the procedure, in any case, it satisfies over the long haul.

2). Refreshing The Schema Of API Testing

The schema– at the end of the day, the information organizing that handles solicitations and reactions for the API– should be kept up all through the testing procedure. Any updates to the program that make extra parameters for the API calls should be reflected in the construction set up.

3). Testing Parameter Combinations

APIs handle correspondence between frameworks by relegating information esteems to parameters and going those parameters through information demands. It's important to test all conceivable parameter demand blends in the API to test for issues relating to explicit setups. A bigger venture could finish up doling out two distinct qualities to a similar parameter, or make occasions where numerical qualities show up when content qualities ought to be. Including an extra parameter exponentially expands the number of conceivable blends.

4). Sequencing The API Calls

Much of the time, API calls need to show up in a particular request to perform efficiently. This then becomes a sequencing challenge for the testing group. This procedure can get progressively troublesome when working with various applications.

API Testing Best Practices

Here are 4 of the prescribed procedures that are available to make your testing procedure speedier, smoother and progressively cooperative.

1). Dry (Don't Rehash Yourself)

Read: Database Testing Interview Questions and Answers for Fresher, Experienced

Make a customer for your SUT (System Under Test) before including tests.

You need to abstain from rehashing your code, however, numerous tests expect you to address similar segments or address comparative activities. In these cases, you can make a lodge library to wrap your test demands by making the utilization shorter and progressively straightforward all the while.

2). Lucidity

Compose clear tests that effectively empower investigating.

While tests are running effectively they require no consideration or time. At the point when tests begin coming up short, assets should be assigned to discover the reason for disappointment. This procedure might be very tedious amid the item advancement and go similar to pushing due dates or cutting new highlights from your item.

3). Mapping And Execution

Structure the tests to keep running under various SUT arrangement alternatives.

This test ought to be structured with the goal that you are not constrained by the framework. They ought to be configurable to keep running in any of your workplaces under various arrangements and give an unmistakable picture to every one of them with a split report.

The more adaptable the tests are, the less exertion is required when they are rendition part, in light of various client demands or when there is a noteworthy change in the item conduct under various designs/conditions.

4). Requirements And Cleanup

To concentrate on the segments right now under test, split the test into three areas:

• Plan (Setup): The Setup makes every one of the conditions and assets required for testing the segment under test. Disappointments in setup ought not to demonstrate the test as bombed but rather as "Not Executed" in light of the fact that that implies that the disappointment we experienced is in an alternate part and not the segment presently under test.
• Execution (Test): Execute the test that utilizes/depends on the readied segments. Also, confirm/attest the result coordinates the normal outcome
• CleanUp (Teardown): Teardown is the post-test arrange in which we erase or reset framework assets that were made or altered as a major aspect of the test.

Conclusion

Application Programming interface (API) testing is a novel type of programming testing and especially important for the organizations that embrace a constant incorporation, integration and reconciliation process. Building API tests amid advancement of any product or administration has broad advantages crosswise over groups, right down to how your client encounters the products and their reaction to it. Making product software that your intended interest group will love is fundamental to the accomplishment of your business and by having your APIs tried thoroughly, you will guarantee a solid method for accomplishing.