Application Programming Interface is the main channel through which two software systems interact and exchange data using direct software links or calls. Therefore, API testing is a collection of API calls and links run by other software applications to determine whether they meet the functionality, reliability, performance, and security threshold. The trained programmer mainly does API testing since they follow a procedure, which requires one to use a testing tool in running the API as well as the formulation of a code for the API Testing.
Various tools that meet the API Testing criteria include Parasoft SOAtest, Runscope, Curl, Check, dotTest, Postman with jetpacks, IBM Rational Test Workbench, TestPlant Eggplant Functional, and Tricentis Tosca among others. The code should be set up for API Testing to take place, which captures all the API outputs obtained during the test and give the expected results.
The API Test works in a sequence where there is the retrieval of data from the database and store. It moves into the logic tier where the data is processed in stages/layers and makes the decisions after which it does a translation into information that a user understands. API Testing is therefore done to ensure that the API’s give the right response from various requests and in a required amount of time. It also responds to any security problem accordingly. API Testing involves some activities including functional testing, detecting a runtime error, load testing, security testing and unit testing among other.
Setting up of an API testing involves creating an environment for the API Testing, which is a little bit complicated. After that, the servers and databases get set according to the requirements of the application and after completion of everything; the API runs a test for functionality. API Testing comes with a bunch of challenges that include parameters combination and selection, lack of GUI in the testing of the application. There are a variety of services that offer this such as Load View-Testing, and Apica.
Additionally, knowledge in coding is necessary to all testers who may not have the expertise on the same, call sequencing, and verification and validation of output may be a difficult ordeal for the testers too. API Testing gets extra attention since a small error leads to problems with application.
API Testing involves testing software through application programming interfaces, which give it the name (APIs). The testing can either be direct or integrated but the purpose it to ascertain different expectations such as reliability and performance. In addition, APIs test for the functionality as well as the security of the software. APIs, on the other hand, consists of protocols as well as standards, codes and tools that are the making of software. Combined, these attributes in APIs help in the testing phase of the software. The importance of APIs lies in the production or design of software that meets the market standards as well as user requirements. There is also the aspect of enhancing user experience which is still part of business completion.
To understand how API Testing works, it is best to understand how software or applications are made. Applications consist of three separable parts. One is the data tier where data is retrieved from databases, file system as well as stored. Second is the logic tier which can be described as the brain of the application. It processes data, coordinates the application, makes logic decisions and process commands all made up of the API. Lastly, there is the presentation tier which is the top most layer of the software and serves as the user interface. The purpose of this tier is translating tasks into understandable data for the users.
From the above, the purpose of API Testing is clearly presentable as establishing the robustness of the APIs. As indicated in the logic tier, there are various types of API Testing. These are unit testing, security testing, WS or compliance testing and runtime error detection. There is also the web UI testing, load testing as well as functional testing in addition to unit testing. However, the testing cannot work without the necessary API testing tools. Examples of these tools include Microsoft Visual Studio and IBM Rational test workbench. It is understandable that each entity involved in software production has its API testing tools. Also, it becomes apparent that it is not possible to be in the software business without API testing tools.
API testing is a testing software which tests programming interfaces for functionality, reliability,security and performance to determine if they meet expectations. Most web applications are three tier, architectural models which include presentation tier, logic tier, and data tier. under normal circumstances, none of these tiers know anything about the others(tier) like the platform, technology or the structure. Each of the tiers runs on a different server and as the test, needs arise, anyone tier could be swapped out. Any one of the tiers could be replaced with your choice of the test tool.It is better to getting testing involved in a designed process as early as possible because testing becomes more difficult if the boundaries between the tiers start to blur.
Of all the three tiers the logic tier is the API this is where the business logic belongs. it is not uncommon that logic tier of your application might have more complexity and technologies like the web server, and message queue will make up this tier.
There are challenges with API testing. API is an interface interpreted by the computer. The input and the outputs are in the form of text format.To interpret the input, output text messages is easy for humans to sufficiently test it an in-depth knowledge of the internals of the application is absolutely necessary. There are two different testing methods white box testing and black box testing and there is some difference between both the testings. The Overall functionality of the application is taken into account by the tester in black box testing just checking the outputs and exercising the inputs. In white box testing, the testers attention is towards the operation of the application like the path that the data could travel through the application is of main concern to the tester. API testing normally includes the white box testing method.
Looking at the positive paths through the application is not really testing but checking the testing software fulfills all the business requirements and functions optimally is the main objective of testing. API testing is more suitable for continuous testing and test automation than GUI testing. API system is the most stable interface to the system under test because it can sufficiently verify functional paths. It is easy to maintain test at API layer.
Types of API testing: It involves Functional testing, Unit testing,runtime error detection, web UI testing, security testing,load testing and compliance testing (from companies like LoadView--and you can read more about their product here).
API testing tools: There are nine testing tools that met the criteria of API testing.They are Parasoft SOAtest and Development Testing Platform, Borland Silk Test and Silk Mobile, IBM Rational Test Workbench, CA Application Test, Tricentis Tosca, Microsoft Visual Studio, HP Unified Functional Testing and Business Process Testing, SmartBear Ready, and TestPlant Eggplant Functional.