Web services and web service testing are two remarkable and extremely crucial processes that are garnering excessive importance day-by-day, which is further making it vital for software engineers to delve into a detailed discussion about them. Ergo, to simplify this for you, following is an elaborated and comprehensive discussion on web services and web service testing. So, scroll down the details and find relevant information on the following topics:
- What is Web Services?
- Importance of Web Services.
- Introduction to Web Service Testing.
- Steps for Web Service Testing.
- Types of Web Service Testing.
- REST vs SOAP.
What is Web Service?
Over the last few years, web services have gained extreme popularity in its usage and practise. From small businesses to huge organizations, every individual is investing in web services and enjoying its numerous benefits. The term ‘Web services’ can be defined as the mechanism or a medium of communication through which two applications or machines exchange information irrespective of their underline function, architecture, and technology. Other features of web services are:
- It is any piece of software that makes itself available over the internet and uses a standardized XML messaging system.
- These are self-contained, modular, dynamic applications that can be described and published on the network to create products and supply chains.
- These applications can be local, distributed or web based.
- Generally use HTTP or HTTPS protocol over the application layer computer network, where applications sends requests and transfer data through XML or JSON.
- The functionality offered by the a web service uses a the Web Services Description Language, which is an XML-based language.
- A WSDL description of a web service provides a machine readable description of how the service can be called, what parameters it expects and what data structures it returns.
- Web services allow exchange of important data between various applications in a platform independent manner.
- Identified by a URI, a web service is a software system whose public interfaces and bindings are defined and described by the XML.
Why are Web Services Necessary?
Web services are representing a new paradigm in application architecture and development, which are gaining importance in the software industry day-by-day. The increasing popularity of this new technology is because it caters all the major needs of application development. Apart from addressing application development issues, Web Services when implemented by an organization, provides innumerable benefits and advantages. Listed here are some of these advantages that make web services significant among developers and software engineers.
- Interoperability: The biggest and the most important advantage of using Web services is interoperability. As Web services work outside of private networks, it offers developers a non-proprietary route to their solutions. The services deployed by it have a longer life-span, which then offers better return on investment of the deployed services.
- Usability: Another advantage of web services is that it allows the business logic of different system to be exposed on the web, which provides applications a freedom to choose web service that it requires. Moreover, instead of re-inventing the different services for different clients, one can only include additional application-specific business logic on the client-side, which allows them to develop services and/or client-side code using the languages and tools that they want.
- Reusability: Web Services provides not a component-based model of application development, but the closest thing possible to zero-coding deployment of such services. This makes the reuse of Web Service components as appropriate in other services easy and convenient. It also makes the process of deploying the legacy code as a web service relaxing and stress-free.
- Deployability: As web services are deployed over standard internet technologies, it makes it possible to deploy Web Services even over the fire wall to servers running on the Internet on the other side of the globe. Moreover, because of the proven community standards, the underlying security such as SSL is already built in these applications. This standardized protocol further provides several advantages like, wide range of choice, reduction in cost due to competition and increase in quality.
- Cost Effective: Web services uses SOAP over HTTP protocol, which enables users to use existing internet for implementing web services that are cost effective and very affordable. Apart from SOAP over HTTP, web services can also be implemented on other reliable transport mechanisms like FTP.
Introduction to Web Service Testing:
With the recent rise of web services, there is an increasing demand of testing web services. Team of expert developers are dedicating majority of their energy during the process of development in Web Service Testing. Since the web services are composed of loosely distributed over networks, the applications are tested end to end, service by service, and interface by interface. Hence, the aim of web service testing is to:
- Conclude what is expected from the web service with respect to the business requirements.
- Gather and understand requirements, and data standards.
- Design tests cases as per the requirements of the client or the end user, as more data scenarios provide quality deliverables.
- As it is difficult to test end to end business flows with all the possible data scenarios, the web service testing uses automates tool which shortens the testing web service like, Optimyz, SOAP UI, SOAPUI Pro, or with the assistance of various API testing tools.
- Involves tool and writing code for sending and validating request and responses.
- With the assistance of Web Service Testing the team can verify that the actual response is similar or in compliance with the expected output.
- Web service test automation enables test script creation with minimal efforts.
- Helps to validate functionality, security, reliability, usability, compliance and performance of web services.
Steps Involved in Web Service Testing:
Testing of web services can be implemented in various ways, however the basic steps followed by testers while testing any Web service, irrespective of the style it is written into, are quite similar and can be easily identified. Some of these fundamental testing aspects to test any web service are:
- The first step in Web Service Testing is to understand the WSDL file definition.
- Determining the operations provided by the Web Services.
- Finding the XML Request message format that needs to be delivered.
- XML Response message format is determined.
- Develop a test program or testing tool that could send XML message request and receive request as XML message response.
Types of Web Service Testing:
Implemented manually or via automation code and automation tool, Web Service Testing is testing of web services and its protocols (SOAP and REST). This type of testing is mainly done to ensure that the process of communication and exchange of data between two or more software applications is completed without any security or quality breach. The goal of testers during the web service testing is to detect, check and correct any available defect. Moreover, to ensure that the web services are executed exceptionally, testers use different types of web service testing, which takes care of all the elements of Web Services. These categories of testing web services are:
- Functionality Testing:The focus in this type of testing is on the specification review, test case development, test execution, and examination of requests and response. This ensures that the Web Services are functioning according to the specified request and are providing satisfactory results.
- Performance Testing : Testing the performance of web services can be complicated process, however to avoid such a scenario, the tester should clearly mention the thresholds upfront. Another way to simplify performance testing is by having most accurate knowledge of performance requirement. Therefore, an application should be performance tested in the following manner to get the best results:
Security Testing:Web Services are wide open in a network, which are extremely vulnerable to security breaches, such as infiltration of virus and bugs, Denial of Service (DOS) attacks, great volumes of spams and more. To avoid such discrepancies, distinctive security policies have to be imposed at the network level to create a sound Service Oriented Architecture (SOA). Developers design special test cases that aim to direct these policies to ensure that the web service has the best security.
Regression Testing: Developed and deployed across various networks and environment, web services goes through several drastic changes, which can impact its functionality and performance. Hence, it becomes important for the team to implement regression testing, which helps ensure that the web service is working as per the expectations of the team, across all the build and releases. With the assistance of automated regression testing, the team is capable of handling various changes implemented in the web services and its functionality.
Load Testing: Since Service Oriented Architecture (SOA) has broaden the horizon of software engineering, the users accessing web services i s increasing drastically. Therefore, by implementing load testing the team can test the performance of the web service when several users access the system simultaneously or if there is a sudden surge in load or stress on the service.
Compliance Testing: The last type of testing executed on Web Services is compliance testing. It is one of the most important type of testing, which ensures that web services meets all the specified standards, authorizes SOAP request or response messages and authenticates the WSDL definitions.
- End to end testing should be performed from the requester’s perspective.
- During the development performance testing should be done at the unit level.
- At the service level the testing is executed.
- Performance testing is implemented to ensure the functionality under boundary load conditions.
Challenges in Testing Web Services:
While performing web service testing, the team can come across numerous challenges which can impact the effectiveness of testing and can hinder the performance as well as the services provided by a particular application. Some of the challenges encountered by the team during web service testing are:
- Scalability: The biggest challenge for testers during web service testing is to ensure its scalability and security. As the web services are mostly developed and deployed to different platforms, networks, and environments, it becomes hard for the team to assess or have a control over the number of individuals or users connected to the service. This can impact the performance and functionality of the web service, if it is not made suitable for large load scenarios.
- Security: As the team has no control over the internet web services, it becomes crucial as well as challenging for them to implement required security measures. Hence, excessive methods are used by the team to validate the security of the users accessing the web services.
- Lack of User Interface: Absence of lack of user interface in web services becomes another major hurdle during web service testing, as it cannot be tested by the team manually and requires test case creation. To design and create test cases for web service testing it is vital for the team to have necessary programming skills and an in-depth knowledge of web services fundamentals.
- Distributed Across Network: Web services are majorly distributed across various networks, hosted by different operating systems, and deployed in variety of environments, which makes testing even more challenging and complicated for the team. From the performance and functionality of the web services, to its reliability, availability, and security, the team is made to consider all these aspects to ensure the accuracy as well as the success of testing.
- Identifying Correct Tools: The importance of web service tools is monumental, as they play a critical role in making web service implementations successful. Hence, it becomes extremely challenging for the team to identify the right tool for testing that can help them get response that are in compliance with the expected outputs.
Tools Used for Web Service Testing:
Testing of Web Services is necessary to ensure that they perform rightly and respond correctly to the raised quarries. There are several commercial and open source testing tools in the market to test the connectivity, response, and performance of web services. These testing tools perform automate testing for various scenarios, such as functional testing, load testing, performance testing, etc. Some of the most important Web Services testing tools are:
- SoapUI: This is an open source, cross platform testing tool. It can automate functional, regression, compliance and load testing for both SOAP and REST web services. Provides printable, exportable and HTML based at reports at Project, TestSuite, TestCase, or LoadTest level. Records, monitors and displays all the data and supports WS-Security and SSL description.
- TestingWhiz: A codeless test automation tool which comes with web services testing capability. It allows functional, compliance, load testing and mocking of SOAP and REST web services via WSDL interface over HTTP and FTP. TestingWhiz also perform service denial and penetration checks to ensure the overall health of the web services. Plus, it also lets the tester execute end-to-end testing right from Web UI, business logic, to database and ETL without coding needs.
- SOAP Sonar: Provides comprehensive web services testing for HTML, XML, SOAP, REST and JSON. It supports vulnerability tests with XSD mutation and provides comprehensive WSDL and Schema parsing. Apart from these, SOAP Sonar also performs load testing with behaviour modelling and multiple simultaneous loading transactions. The reports provided by SOAP Sonar are in XML, DOC, XLS, PDF, RTF, and RPT formats.
- vRest: It is a tool exclusive for testing, mocking, and validation of REST APIS and Web Services. It also supports testing of web, mobile and desktop applications that interact with the third party AIP and HTTP services. It comes with mock functionality which creates AIP mock within minutes.
- SOATest: It provides robust support for the functional unit, integration, security, stimulation, mocking, compliance and load testing of technologies like REST, JSON, MQ, JMS, TIBCO, HTTP, and XML. It supports more than 120 protocols and message types and continuous integration testing. SOATest provides Chrome extensions to record and play test cases.
Advantages of Web Service Testing:
Web services, along with web service testing is changing the paradigm of software and application development and architecture. It is offering the users several benefits, which is further enhancing the interoperability, usability, and other aspects of software applications. Some of the other advantages offered by web service testing are:
- With the assistance of web service testing the team can enhance the performance and reliability of the SOA.
- It validates full functional test coverage.
- Verifies that all APIs exposed by the applications are operating as per the expectations of the team and other stakeholders.
- Ensure the interoperability, usability, reusability, security, and other aspects of the software and application.
- Simplifies testing for both SOA and REST API based web services.
- One can test web services in a cloud environment.
- Helps reduce testing efforts over regression cycles.
- Web services can be tested through automated testing, which saves testing efforts and simplifies the process of testing.
- Tools can be used by the team to send requests and to validate the response.
Difference between REST & SOAP:
Since the significance of web services is excessively high, it is vital for us to conduct extensive and comprehensive testing on it at all levels. As web services are majorly of two kinds, SOAP and REST, it is important that we understand the differences between these two critical elements. Ergo, here is a comprehensive comparison between REST and SOAP.
|1. It is an abbreviation for Representational State Transfer.
||1. SOAP is an abbreviation for Simple Object Access Protocol.
|2. Defines a set of architectural principles by which data can be transmitted over a standardized interface.
||2. It defines a standard communication protocol specification for XML based message exchange.
|3. REST can use SOAP web services, since it is a concept that can use any protocol like HTTP, SOPA, etc. .
||3. Uses different transport protocols, such as HTTP and SMTP.
|4. It is also known as RESTful Web Services.
||4. This Web Service Description Language (WSDL) defines rules for the message, binding, operations, and location of the service by describing common set of rules.
|5. Unlike SOAP based services RESTFUL web API does not have any official standard.
||5. It uses service interfaces to expose business logics.
|6. These expose the operations as a service of unique resources, which correspond to a specific URL.
||6. SOAP is defined by W3C standard for sending and receiving web service requests and responses.
|7. REST web services are stateless, that is one can test this service by just restarting the server and verifying the condition of the interactions.
||7. With SOAP approach the team does not have to write code into the application layer.
|8. Compared to SOAP, REST requires less bandwidth and resources.
||8. The requirement of bandwidth and resources is more in SOAP web services.
|9. It permits various data formats, such as XML, Plain Text, HTML, JSON, and more.
||9. SOAP web services permit XML data format only.
|10. REST inherits security measures from the underlying transport.
||10. SOAP is well equipped in defining its own security.
|11. REST implementation is simple and more preferred than SOAP.
||11. Though less preferred than REST, SOAP still offers various advantages to the user.
Web Service is the latest technology that has gained immense popularity among developers and testers. From connecting several software applications on the web with wide range of applications all around the world, to providing easy and secures services, Web Services has changed the norm of exchanging data on the web. However, to ensure that this popularity and quality service remains consistent, testing is executed on all web services. Whether you opt for SOAP or REST Web Services, you can find several manual or automation tools in the market, which allows functional, compliance, load testing and mocking of SOAP and REST web services.