Functional Testing of Web Services - Software Test Consulting

Yury Makedonov

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Functional Testing of Web Services Yury Makedonov, CGI

2004 International Quality Conference, Toronto, Ontario, Canada © Copyright 2004 – CGI Group Inc.

September 22, 2003

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Agenda ¾ Why we are getting more and more web services testing ¾ What are web services ¾ What is XML ¾ How to test web services ¾ Test Approach ¾ Tools

¾ Summary ¾ Q&A ¾ Intended audience: Testers without development background September 22, 2004 Functional Testing of Web Services, QAI Conference

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Introduction ¾ Webservices have no GUI. Typically this type of testing is performed by developers. ¾ Independent testing teams started getting more and more webservices testing projects ¾ Why are webservices so special?

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Why web services? ¾ Web services are a simple interface using HTTP protocol. ¾ Web services can be: ¾ developed by one company, ¾ used by another company, and ¾ hosted by a third company.

¾ Such involvement of several companies is a business cases for independent testing of web services.

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What are web services? ¾ What’s in the name Web Services? ¾ Web means HTTP protocol, ¾ Services means request – response.

¾ Web services is a stateless protocol ¾ we send a request, ¾ we receive a response, ¾ we are finished.

¾ Why is this so important from testing point of view? ¾ Because we can prepare independent test cases that are

separate files. This makes our test approach relatively simple. 5

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XML ¾ Web services use XML encoded ?> ¾ ¾ ¾

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Note.dtd: ¾ ¾ ¾ ¾ ¾

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Sample – “Schema Definition” – Schema ¾

Note.xsd: ¾ ¾

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How to learn XML ¾ Do we need to know all intricacies of XML, DTD, and XML schemas to start testing of web services? ¾ No! ¾ With basic XML principles, described above, you can start development of XML test data files! ¾ I recommend an approach for XML learning: ¾ Get sample XML files with corresponding DTD or XSD files

for your new webservices project. ¾ Go through major elements and try matching definitions from

DTD/XSD and corresponding XML data. ¾ Use web sites (e.g. http://www.w3schools.com) or XML books

as additional sources of information. 13

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Testing web services – Test Approach ¾ When testing webservices we use the same approach as for any other testing project: ¾ identify requirements, ¾ Prepare high level test cases, ¾ Document detailed test cases, etc. ¾

What would be an outcome of a test planning phase: ¾ a set of test cases described in plain English language and

based on a requirements document, ¾ a corresponding set of XML files.

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Sample test case ¾

Requirement: ¾ “Location type” can be blank in a request

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Test case brief description: ¾ “Location type” is blank in a request

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XML test data file: ....... 1600 .......

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How to prepare XML test files ¾ How to prepare XML test files: ¾ We have to get a sample XML file from a software developer

and to enter our values of parameters. ¾ This is not so terribly different from a standard GUI testing. ¾ The only difference:

we have to enter our data into “fields” of XML document instead of fields of GUI.

¾ We have to follow a standard testing procedure, familiar to every black box tester and to use standard testing techniques when testing Web Services: ¾ valid and invalid data, ¾ boundary values, ¾ equivalence partitioning, etc. September 22, 2004 Functional Testing of Web Services, QAI Conference

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Tools – to prepare XML test files ¾ What tools to use for XML files preparation: ¾ Whatever you have, ¾ from Notepad ¾ and Microsoft Word ¾ to XMLSpy

¾ My favorite tools are: ¾ Notepad (or TextPad for bigger files) ¾ XMLSpy

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Tools – to execute a test ¾

We have prepared a set of XML files that represent our test cases.

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Next step is to process these files.

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To process XML files (XML requests) we need: ¾ to POST an XML file (to send it to a specific URL and port), ¾ to capture an XML response and to save it into a file.

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We need a tool to do this.

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Tools – to execute a test ¾

Load Testing tools ¾ Natural choice is any load testing tool, designed to handle

HTTP traffic. ¾

XMLSpy. ¾ XMLSpy can POST a SOAP document and capture a

response. ¾

Custom tools/script: ¾ A Perl script or a Java program can be developed to send a

request and to capture a response. ¾

Empirix eTest: ¾ Commercials tool to test SOAP based web services.

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Many more options. 19

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Analyzing results ¾

After we have XML response files we have to compare them against expected results, described in our test cases.

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Typically we have to verify values in some specified fields.

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That task is not so different from a standard GUI testing.

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Regression testing ¾

In case of a regression testing we can use a less time consuming approach.

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We can automatically compare a new set of XML responses to a previous set, using: ¾ WinDiff.exe, ¾ XMLSpy, ¾ MS Windows commands: “Comp” or “fc”

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Summary ¾

Testing of web services is not so different from a standard GUI testing,

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New skills to learn are relatively simple (half a day or a day to learn),

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Typical testing team already has most skills and knowledge required for this type of testing,

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Testing web services can bring additional job and visibility to an independent test team.

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Let’s leverage our skills and knowledge to a new field.

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Let’s test web services.

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Yury Makedonov

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Contact Information ¾ Yury Makedonov (416) 481-8685 [email protected] http://www.ivm-s.com

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References ¾

The above examples are from: CGI projects http://www.w3schools.com, http://www.intertwingly.net/stories/2002/12/20/sbe.html

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You can find more information on XML on these and many other web sites.

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