Bugs in the Wild, Testing

BOM – Byte Order Mark

Because we encountered another hidden encoding issue as part of test data, here are some information about BOM and why this might be interesting in general for everyone working with a computer beyond Excel and Word.

Before you educate yourself, here is the tool to own to see such a problem easily. Most of all editors hide that information and so you might scratch your head why some data is failing with strange error messages. Get xxd and you will see with other eyes:

$ xxd /tmp/2018-01.csv 
0000000: efbb bf23 4375 7374 6f6d 6572 204e 756d  ...#Customer Num
0000010: 6265 722c 5265 6164 204f 6e2c 506f 7765  ber,Read On,Powe
0000020: 7220 4d65 7465 7220 5265 6164 696e 670d  r Meter Reading.
0000030: 0a30 3030 312c 3230 3138 2d30 352d 3032  .0001,2018-05-02
0000040: 2c35 3030 0d0a                           ,500..

The first marked bytes are the magic and now head over to the Wikipedia to read more about BOM: https://en.wikipedia.org/wiki/Byte_order_mark

Interesting Reading, Java, Software Development

Java Training Sessions

Today we are going to publish four of our Java training sessions so you can use the material and benefit from it.

Let’s get started with four direct links to extensive material that might help you to understand Java or code quality better or just help you to reflect on topics you already know.

  • The Java Memory Model: Why you have to know the JMM to understand Java and write stable, correct, and fast code.
  • Java Memory Management: Know more about the size of objects and how Java does garbage collection.
  • High Performance Java: All about the smart Java internals that turn your code into fast code and how you can leverage that knowledge.
  • High Quality Code: The anatomy of high quality code that supports longevity, cross-team usage, and correctness. This is not just about Java, this is about good code in general.

Show a little patience when loading the training, these are all large reveal.js based slide sets. Use the arrow keys or space to navigate. Because the slide sets are designed to be interactive sessions, in many cases, not the entire slide context is revealed at once but block by block.

We publish these training sessions because they are also based on openly shared material, it greatly helped us to advance and understand, as well of course advertise a little what Xceptance might be able to do for you.

We will release more of our material in the next weeks and month, so everybody can browse and learn. This won’t be limited to Java and also cover material about approaching load testing, how to come up with test cases, and more about the modern web and its quality and performance challenges. Of course there will be more Java material too. You can get a glimpse of it when you just follow this link and page through the slides: The Infinite Java Training. Please remember, not all material is complete yet.

If you like the material and you need an audio track aka a real presentation, please talk to us. If you see other training needs in the area of quality assurance, testing, and Java, please contact to us.

More to come.

Open Source, Software Development, Xceptance, XLT

Thuringia’s Open-Source Prize for XLT

Wolfgang Tiefensee, Thuringia’s Secretary of Commerce, in conjunction with the board of directors of the IT industry network ITNet Thuringia, awarded the first Thueringen Open-Source Prize to three companies, all of them software companies based in Jena: TRITUM, Xceptance and GraphDefined.

Open Source Prize Title Picture Second Place

It is an honor for Xceptance to be the second-place winner of this competition. This result clearly demonstrates that open source as a component of commercial products can be a clear competitive advantage. XLT incorporates a number of open-source projects, including Apache HttpClient, Jetty, HtmlUnit, JUnit, and the Apache Commons libraries. As part of developing XLT, Xceptance is involved in testing and providing feedback for these projects, thus giving back to the open-source community.

While XLT is itself not open source, Xceptance does provide the software free of charge and with virtually no usage restrictions, so for most applications there is no noticeable difference to open-source software.

Performance, Testing

Comparing Measured and Perceived Loading Times

TL;DR: The perceived loading time is what shapes the user’s impression of the speed of a website, but measuring perceived loading time is difficult. There are technical loading times available but it is not clear if these times can be used in any meaningful way. This master’s thesis verified whether the perceived loading time can be easily correlated with any technical loading time, such as FirstPaint for instance. The result shows that a page with a fast loading time from a technical point of view is not necessarily perceived as fast by the user and vice versa. Therefore it is not sufficient to rely only on technical measurements and disregard the user’s perception.

Client-side performance is a big deal. There are various studies on the relationship between loading time and critical success factors such as usability of online shops, customer loyalty and sales. Yet a page with an objectively long total loading time could still be perceived as fast by the user, as the visible part of the browser window has already loaded and invites the shopper to interact with the page.

In her master’s thesis “Client-side performance: Comparison of measured and perceived loading times of online platforms in the B2C sector” Bastienne Sauter scientifically evaluated this discrepancy between the technically measured and the perceived loading times. By implementing automated tests with the automation tool XLT (Xceptance LoadTest), the loading times (timestamps recorded: domLoading, firstPaint, domInteractive, domContentLoadedEventStart, domContentLoadedEventEnd, domComplete, loadEventStart and loadEventEnd) of fifteen German e-commerce stores were measured over a longer period of time, both for desktop and mobile. For each store and timestamp, a ranking of the average loading times was calculated for each device.

In order to determine the empirical values for the perceived loading time, an interaction study with test groups of students and of Xceptance employees was conducted. Each group consisted of 25 persons, so a total of 50 people took part in the study. The participants had to open predefined pages of an online store and assess the loading impression. The user’s perception was evaluated using suitable scales. In this manner a score value was determined for each store among the two test groups. Each participant evaluated only three of the 15 stores in order to keep the effort manageable. In other words a store was covered by five test persons of each group (according to Nielsen and Landauer, a total of five respondents per store is sufficient for usability tests to be meaningful and to cover the majority of usability results). To ensure comparability of the results, the interaction study was conducted on the same devices and at the same location to avoid different bandwidths of the internet connection. Furthermore the test session for every person was set up in a way to avoid stress and create a normal daily usage situation.

Comparing the measured technical loading times with the perceived ones from the study, it showed that they differ clearly from each other, with no significant correlation.

To get an impression of which timestamp could be most relevant for the perceived loading time, the distances of the positions in the rankings were calculated. The smallest deviations for the desktop showed the timestamp domContentLoadedEventEnd, while the timestamp firstPaint could be most relevant for mobile devices.

Sum of the distances between the different positions in the rankings
Sum of the distances between the different positions in the rankings

As a conclusion, it is neither sufficient nor purposeful to consider only the technical measurements for the evaluation of the client-side performance, because the user’s perception deviates significantly from the technical measurement. This proved to be true both for informed insiders (represented by company employees) and also the uninformed public (represented by the students).

The results raise further research questions, especially how quality key figures for the perceived loading time can be recorded and contribute to the evaluation of online stores. In the literature, user-centered key figures such as FirstMeaningfulPaint are cited for this purpose. Whether these figures are in fact useful to represent the perceived loading time, however, is unclear and requires further investigation.

Illustration of Load Metrics by Google under CC-BY-3.0 

Misc

XLT 4.12.1 Release

Xceptance has released version 4.12.1 of its load testing and test automation product Xceptance LoadTest.

Test Framework

  • Fix: Our timer recorder extensions for Chrome and Firefox did sometimes report invalid request entries that could not be processed by the report generator. This could happen for requests that did not complete.
  • Fix: If a test case deliberately caught an exception / assertion error and afterwards ran to completion successfully, it might nevertheless be marked as failed in the load test report.
  • Improvement: Selenium has been updated to the latest version 3.141.59 and HtmlUnitDriver to version 2.33.3.

Load Testing

  • Improvement: The new AWS data center in Stockholm, Sweden (eu-north-1) is fully supported by ec2_admin now.

Make sure to read the full online release notes.

As always, this upgrade is free and don’t forget, XLT itself is free as well. You don’t have an excuse to skip performance testing or rely on lame simple test cases anymore.

XLT

XLT 4.11 was released

Xceptance released version 4.11 of its load testing and test automation product Xceptance LoadTest. This is a feature release. We recommend upgrading to this newest version.

Here is a selection of the most important changes:

  • HtmlUnit and Selenium have been updated
  • You can run a test case with only a single data set at development time
  • XLT picks a data set automatically when a test with multiple data sets is part of a load test
  • There is a new command-line tool to automatically evaluate a test report based on your defined success criteria
  • The XLT Jenkins plugin returns a result object now with all the details when used in a pipeline
  • The XLT Jenkins plugin can now create a comparison report

See our release notes for more details. As always, this upgrade is free and don’t forget, XLT itself is free as well. You don’t have an excuse to skip performance testing or rely on lame simple test cases anymore.

Automation, XLT

Firefox 57 Changes and XLT

Firefox 57 is going to deliver a fundamental change that will affect XLT Script Developer.

As you might know, Mozilla decided to completely remove the support for XUL/XPCOM-based extensions (aka legacy extensions) in favor of extensions built upon the WebExtension API. This cut will take place on November 14, 2017, with the release of Firefox 57. Additionally, Mozilla will refuse to sign updates of legacy extensions at some point in the near future, although the exact date is not determined yet. See the Mozilla Add-ons Blog for an up-to-date timeline.

The consequence of this breaking change is that XLT Script Developer cannot be installed in Firefox 57 and higher. Also, an already installed XLT Script Developer cannot be used any longer.

We at Xceptance have been aware of this development. Over the course of the last year we have been busy evaluating several alternative options. As you might recall, we also conducted a survey back in the spring to collect your feedback.

Based on our findings and your input and after long discussions, we came to the conclusion that the feature set and comfort that had been offered by XLT Script Developer and its way of writing web automation cannot be recreated using the alternative Firefox APIs.

Therefore, we regret to announce that Script Developer is discontinued. Consequently, we don’t recommend starting new test projects based on Script Developer and XML script test cases. To be able to continue to use the features of XLT and the advantages it offers, we suggest you use XLT’s Java-based API.

If you are able to use Firefox 56 or Firefox 52/ESR, maybe in parallel to an updated version of Firefox, you can continue to work with XLT Script Developer as well as execute all your test cases as you have been.

We are aware that this decision might disappoint many of you and may leave open questions. For more information on what shaped this decision and what your options are for maintaining your existing XML script test suites in the future or migrating them to another base, please see the Q&A section below.

Q&A

Why did Mozilla decide to abandon legacy extensions?

By design, legacy extensions have not only full access to your local file system but also to the entire browser and thus to all the pages you visit. This has been causing privacy and security issues and hence Mozilla decided to abandon the API to address these problems.

Why isn’t XLT Script Developer being ported to the WebExtension API?

The possibilities offered by the WebExtension API are very limited. One such limitation, and the most important one, is that access to the local file system involves a user interaction for each and every file to save or read. This would make Script Developer simply impossible to use.

Further restrictions apply. Most of them are related to accessing and manipulating session and browsing data such as cookies or cache. In the end, Script Developer would only be able to support a very reduced feature set.

And last but not least, the outcome of our customer survey revealed needs which cannot be met by such a modest visual, non-programming approach to writing tests. See the next question for more details on the feedback we received.

Why won’t XLT Script Developer be ported to another platform?

The outcome of our survey was that users wanted a tighter integration with Java/IDEs, more commands, more ways to customize things, better flow control, and more flexibility with test data. At the end of the day, this is a full programming approach and turning the XLT Script Developer into another programming environment couldn’t address all these points.

We also believe that the concept of XML script test cases with their limited capabilities are no longer appropriate for modern testing needs. Therefore we have decided to give it up in favor of the opportunities a real programming language provides.

Can I continue to use XLT Script Developer with Firefox 56?

Yes, but at your own risk. Remember that your browser cannot be updated and therefore will not receive any security fixes. Furthermore, it may not be possible to install any Script Developer updates as this Firefox version accepts signed extensions only. And Mozilla might stop signing legacy extensions any day. See below for a better solution.

Can I continue to use XLT Script Developer with Firefox 52/ESR?

Yes, absolutely. That is the recommended way to go, at least for the next months. First, Firefox 52/ESR (Extended Service Release) will be updated with security fixes until May 2018. If you continue to use Script Developer after that date, though, you do so at your own risk. Make sure that you use this browser version for scripting only.

Furthermore, Firefox 52/ESR can be tweaked to install legacy extensions even if they are not signed by Mozilla. This way, you are still able to install Script Developer updates in case Xceptance provides some in the future.

Will the XLT framework still be able to replay XML script test cases?

Yes, XLT will continue to interpret and execute your existing XML script test cases as JUnit tests via their wrapper classes.

How to migrate existing projects?

Export all your existing XML script test cases to Java (Scripting API). From this point, you maintain your test cases in your favorite Java IDE instead of the XLT Script Developer. Since the concepts and commands are the same as in Script Developer, you will be on top of things quickly.

Instead of running your XML test cases in Script Developer, you would now run your Java-based tests as JUnit tests using your preferred WebDriver either from your IDE or using a continuous integration system.

Since your code base is plain Java now, you are free to add all the things that you might have missed in the past.

Note that XLT 4.10.0 will ship with some enhancements for Java-based test cases. For instance, Script Developer will provide an alternative export template that produces more compact code. Additionally, writing test cases directly in Java will be more comfortable as well. Stay tuned for the upcoming release and find all the details in the release notes.

Make sure you subscribe to our low-volume XLT release and news mailing list.

How long will you release XLT Script Developer updates?

TBD. Future updates of Script Developer will be bug-fix releases only (shipped as unsigned extensions once Mozilla stops signing legacy extensions). Don’t expect any new features.

Are there any other options?

Yes. There are forks of Firefox that promise to continue supporting legacy extensions while being kept up-to-date at the same time. For instance, Script Developer installs and runs nicely in Waterfox. However, we cannot predict how long this will actually work.

Xceptance, XLT

XLT 4.9 has been released

Xceptance released version 4.9 of its load testing and test automation product Xceptance LoadTest. This is primarily a 3rd party update release, but also delivers some improvements.

Here is a selection of the most important changes:

  • Script Developer supports Firefox 53
  • Selenium updated to version 3.4.0
  • Better reporting of JavaScript errors in script test cases
  • Master controller displays the configured load profile
  • Load test reports can be created for a subset of agents
  • Load test reports shows the number of entries in data tables and shows summary values when filtering the table
  • Demo app server ports can be reconfigured easily

Script Developer

Script Developer has been made compatible with the latest available Firefox version, while outdated versions are not supported any longer. Script Developer runs on Firefox 45/ESR up to 53 now.

Update Instructions: Firefox will not auto-update older versions of Script Developer to 4.9.0. You will need to do this manually. Please remove the currently installed version first and afterwards install the new version by simply dragging and dropping the file xlt-scriptdeveloper-4.9.0.xpi onto Firefox. Auto-updating within the 4.9.x product line will then work as usual again.

Alternatively you can visit the Mozilla Add-On marketplace and install Script Developer from there (https://addons.mozilla.org/en-US/firefox/addon/xceptance-script-developer/). Please make sure you uninstall your locally installed version first.

Framework

XLT now ships with Selenium 3.4.0. Make sure you update your locally installed driver binaries to the latest available version. This is especially true for geckodriver. In case you experience issues with geckodriver / Firefox, you might be better off running FirefoxDriver in legacy mode. The legacy mode is more mature.

All other core libraries have been updated as well. This also includes HtmlUnit for an improved browser emulation.

The XLT framework also comes with some functional improvements. In case a JavaScript expression in your script test case could not be evaluated successfully for any reason, the root cause will now be listed as part of the exception message. Libraries that make use of Java’s built-in logging framework do no longer log to the console, but to XLT’s log file.

Load and Performance Testing

The Mastercontroller now prints the configured load profile to the console when starting a load test and also when displaying the current status. This helps to spot test configuration mistakes earlier. Intermediate results downloaded, while a load test is still running, will now be flagged to distinguish them from final results.

The load test report shows the number of entries in a data table, and when filtering a data table, the footer row is updated accordingly. Load test reports may also be created for only a subset of the agents. You might remember that version 4.8 already delivered the ability to render reports for specific test cases only.

Last but not least, ec2_admin prints more details about running AWS machine instances and lets you review your choice before actually terminating running instances.

Demo App Server / Posters Store

The app server that hosts our demo applications uses ports 8080 and 8443 by default. Since these ports are often already used by other applications, you can now reconfigure them easily.

Our demo application Posters Store now runs with HTTPS only. Any HTTP request will be redirected to use HTTPS.

Sounds interesting? More details can be found in the release notes of XLT 4.9.

Software, Xceptance, XLT

Release of XLT 4.8

XLT 4.8 is primarily a technology update release, but also comes with some new features.

First and foremost, XLT now ships with Selenium 3, the new version of the WebDriver library. All other core libraries have been updated as well. This also includes HtmlUnit for an improved browser emulation. Beginning with this release, XLT requires Java 8 to run.

The XLT framework also comes with some functional improvements. XLT now supports OperaDriver out of the box and can run FirefoxDriver in either the new Marionette mode using geckodriver or in the “old” legacy mode. When you drive Firefox via XltFirefoxDriver, you will get a much more detailed result browser now, with almost the same request and response details that you already know from XltDriver. Any values that you programmatically add to the newly introduced value log of a session are shown in the result browser as well. Furthermore, most of the XLT framework properties can now be configured not only globally, but also specifically for a certain test scenario.

For load testers, there is something in the box as well. If you use the AWS EC2 cloud a lot, you will be glad to hear that the new AWS data center in Ohio is now fully supported. The load test report has been tuned to become usable much faster, even with lengthy pages such as the Requests page.

Last but not least, the Poster Store demo application and the XLT Jenkins Plug-In have both been updated. If you ever wanted to load-test your WebDAV server, there is now a new demo test suite for that.

Sounds interesting? More details can be found in the release notes of XLT 4.8.