Undo Font Size Bug in OpenOffice.org's Writer v1.1.1

 

Summary

OpenOffice.org's Writer 1.1.1 word processor has a bug that causes the program to incorrectly undo a font size change in an empty paragraph (a new line that has no characters in it yet). If the user changes the font size and then uses the Undo function to remove the change, the font size will revert to the default size setting.

Application Description

OpenOffice.org is an office suite including word processing, presentations, and spreadsheets. Writer is part of the OpenOffice.org suite and is used to create documents and letters. OpenOffice ships in most versions of Linux or can be downloaded for free from their official site.

Test Design

This example demonstrates the use of Combination testing. In Combination testing, we test two or more variables at the same time. We do this type of testing both to observe variables in conjunction (so as to verify their interoperatibility) and to increase the productivity of our testing. For example, by testing three different variables together, we can verify whether any one variable has a damaging effect on the others and we can also verify that all three variables work correctly.

Combination testing in programs such as word processors is a very important testing technique. With so many variables that need to work together, it is almost impossible to isolate any one. For example, just to type one character, we are utilizing all of the font characteristics (such as font size, face, color, decoration, etc., - literally hundreds of variables), the page properties (spacing, borders, indentation, alignment, etc., - again, hundreds of variables), auto-saving, background operations, and too many more to list. Even if a variable is set to off, that is still a setting that can affect the performance of another variable. With combination testing, we take much of this into account, examining how well this interaction performs.

For this presentation, we will simply be working with a new document, adding some text and making changes to the font size. What we expect from Writer is that when performing an undo, no matter when or where we perform it, Writer will correctly revert us to the state we were in previously. All the settings should be reverted to exactly what they were before the change.

Performing the Test

  1. Open OpenOffice.org's Writer and use File->New to create a new document.

  2. Change the font size to 44 (or any size other than the default 12).
  3. Press Enter on your keyboard a few times to create some blankspace.
  4. Type in any text on the last line:

  5. Move the cursor to the previous line and change the font size to 88 (or any size other than 12 and the size you are currently on):

  6. Now use Ctrl-Z or Edit->Undo to undo the font size change.

Results/Relevance

Notice how in the above picture, the cursor has become very small and the font size says that it has returned to size 12? If you undo a font size change on a paragraph that contains text, there is no problem. Writer can correctly undo font size changes, where the font size is returned to the setting it was at immediately before the change, but when combined with another variable, an empty paragraph, the undo fails to run correctly.

Though a bug like this is really only a small nuisance, there are two reasons to fix it. First, convenience. For the program to be as accessible as possible, it should be as convenient as possible. If it makes undesirable changes to settings that it has not been asked to do, this hinders accessibility. Second, finding one bug is often times a sign that there are more bugs, and potentially more complex and dangerous bugs.

Similar Tests/Additional Notes

This was a simple example of combination testing (although effective). Apply this same concept to even more variables, such changing page properties while typing, or changing font settings inside templates that have already set up other font settings.

Configuration Notes

Testing OpenOffice.Org's Writer v1.1.1 on:

Created 10 June 2004 for the CSTER

All images and written material ©Copyright Sam Oswald 2004

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