The Magazine for Professional Testers

June 2010

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Performance Testing

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76 The Magazine for Professional Testers www.testingexperience.com

Case study: Testing of Mobile Positioning Web Services

by Dr. Andres Kull

© iStockphoto.com/kryczka

The case study was conducted to test Reach-U’s (http://www.reach-u.com/) Workforce Management (WFM) application, a web-based mobile positioning application developed by Reach-U. WFM is an application that can observe a workforce’s movement history, location and send SMSs to personnel via the web browser client. WFM’s users are primarily companies that would like to track and plan their workforce locations in real time.

Figure 1: General architecture of WFM

The case study was performed to evaluate the applicability of model-based testing for testing web services via functional and load testing – use cases where an operator uses a WFM web-client to locate targets were tested. Only servers that are part of WFM were in the scope of the implementation under test (IUT). A web client was simulated by the test system. It is worth noting that testing the functionality of the web client itself was out of the scope of the case study.

The following aspects were evaluated in the case study:

• Overall feasibility of model-based testing technology for testing web services.

• Applicability of model-based testing technology for load testing.

ImplementationIn the case study we used a test generator producing TTCN-3 test scripts automatically from the State Model (UML) of the IUT,

a full-feature TTCN-3 test development and execution platform and the JMeter (JMet) load tester. Additionally, a system adapter was developed to communicate between WFM and the TTCN-3 test development and execution platform as well as the JMeter load tester.

Firstly, the TTCN-3 scripts generator was used to generate TTCN-3 test cases from the system model. The test cases generated from the model were executed on the TTCN-3 test development and execution platform. Test cases controlled the execution of JMeter as well. JMeter was used to generate the load for the server infrastructure of WFM. The test cases instructed JMeter to vary the load. Therefore, the test cases were communicated to two counterparts – the IUT and JMeter. In between, the system adapter was developed. The system adapt-er connected to the TTCN-3 test de-velopment and execution platform to WFM and JMeter. The interface of the system adapter towards WFM provided HTTP message traf-fic over TCP/IP. In this way the test

cases ran on the TTCN-3 execution platform and simulated the WFM web-client. The interface of the system adapter to JMeter al-lowed JMeter to be controlled by HTTP GET messages over TCP/IP.

Figure 2: The test environment of the WFM

77The Magazine for Professional Testerswww.testingexperience.com

Results• Overall feasibilityofmodel-basedtestingtechnologyfortestingweb

services.

WFM is a complex distributed web application consisting of many server ap-plications distributed/duplicated on different hosts and protected by a load balancer from overload situations. The case study demonstrated the feasibil-ity of the model-based testing (MBT) technology using TTCN-3 script’s auto-matic generator for functional testing of an IUT interface over web services.

• Applicabilityofmodel-basedtestingtechnologyforloadtesting

In the case study, the load tests and functional tests were used in parallel to test the IUT. The case study demonstrated the applicability of the model-based testing in general for usage in load tests to increase the quality of overall testing. Moreover, it showed that MBT technology could be used beyond the borders of traditional functional black-box testing. In the case study, the functional tests were generated out of the WFM model and used in conjunction with a load tester in order to prove the expected behavior of the IUT in the event of heavy loads.

Andres Kull is a co-founder and CEO of Elvior OÜ. Elvior is a software testing services and tools company specialized in embedded and distributed software testing. Andres has a PhD (2009) in Informatics and Communication and an MSc (1985) in Control Systems from the Tallinn University of Technology. His 25-year professional career spans the areas of control systems for the chemi-cal industry and model-based enginee-ring of software-intensive embedded and distributed systems. Andres has held researcher positions at the Tallinn University of Technology and Technical Research Centre of Finland (VTT). His current specialities, in addition to the management of Elvior, are embedded software development and testing, model-based testing, and TTCN-3 tes-ting and test tools.

Biography

- the tool for test case design and test data generation

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