Opera Encoding Problem


In this example we are going to perform Function Testing by making sure that the user can change the encoding in which a page is displayed using the Encoding function. Opera v7.21 (Windows version) is unable to display web pages after the encoding is set to UTF-32, even if it is set back to the default after that. In addition the application starts to consume large amount of resources.

Application Description

Opera is a Web browser developed in 1994. Its developers claim that it is the fastest and most standards-compliant browser today. It is available for all popular operating systems. (Source: www.opera.com).

Users can change the character encoding for the currently active page by using the View -> Encoding function. In this test we will focus on the UTF - 32 encoding (for more information about UTF - 32 encoding visit www.unicode.org).

Test Design

This example demonstrates the use of Function Testing.

This is the list of functions in the View menu. For our test we will focus on Encoding and more specifically on Unicode encoding.

We would navigate to a web page and try different encoding settings.

It is impossible for a web page to look the same in all four Unicode formats (it will be unreadable in some of them). We would expect that the application will handle this fact properly, without affecting other parts of the program and general stability.

Performing the Test

  1. Start Opera and navigate to a web page (www.google.com for example).
  2. Start Windows Task Manager to view what kind of resource Opera is using. Currently on my machine, it is 0% CPU usage and 13,532 K memory usage.

  3. Notice that the default encoding is Automatic selection. Set the encoding to UTF - 32


The web page is not displayed but this can be expected since the page probably wasn't encoded in UTF- 32. The problem is that the CPU usage has risen to 98% and the memory usage has risen to 133,180 K. Closing and starting again doesn't help. In addition, if the encoding is set back to Automatic selection, the user will still be unable to use the browser (See similar tests). To solve the problem, the user has to switch to Automatic selection and then restart the browser.

As a result of this bug, the browser will look to the user as if it has crashed and is unable to work properly again. Some users might not find out the solution and might think that the only way to fix the problem is to reinstall the application.

Similar Tests/Additional Notes

After we have set the encoding to UTF - 32, we can set it back to Automatic selection to see if this will solve the problem. Open another window and try to load www.google.com in it (with encoding set to Automatic selection)


Surprisingly, the page is not showing even though we restored the default settings.

We can also try the rest of the possible encodings. For example setting the encoding to UTF - 8 displays the page correctly. Setting the encoding to UTF - 16 displays unreadable characters on the screen (This is not a bug because other browsers show the same thing, meaning that the page was not encoded for UTF-16). In both cases the performance does not degrade.

Configuration Notes

Testing Opera Software's Opera 7.21 (trial version):

Created 04 June 2004 for the CSTER

All images and written material ©Copyright Georgi Nikolov 2004

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