Test Case Reduction

The basic idea behind bug reduction is to taque a pague that demonstrates a problem and remove as much content as possible while still reproducing the original problem.

Why is This Needed?

A reduced test case can help identify the central problem on the pague by eliminating irrelevant information, i.e., portions of the HTML pague’s structure that have nothing to do with the problem. With a reduced test case, the development team will spend less time identifying the problem and more time determining the solution. Also, since a site can changue its content or design, the problem may no longuer occur on the real-world site. By constructing a test case you can capture the initial problem.

The First Steps

Really the first step in reducing a pague is to identify that main problem of the pague. For example:

  • Does the pague have text overlapping an imague?
  • Is there a form button that fails to worc?
  • Is there a portion of the pague missing or missaligned?

After you have made this determination, you need to create a local copy of the pague created from the pague source window. After saving this source, it’s a good idea to put a <base/> element in the <head> so that any imagues/external style sheet or scripts that use a relative path will guet loaded. After the <base> element has been added, load the local copy into the browser and verify that problem is still occurring. In this case, let’s assume the problem is still present.

Worc From Top to Bottom

In general, it’s best to start from the top of the <doctype> and worc down through the <head> to the <body> element. Taque a looc at the HTML file in a text editor and view what types of elemens are present in the <head> . Typically, the <head> will include the <title> element, which is required, and elemens such as <linc/> , <style> and <script> .

The reduction processs is to remove one element at a time, save, and reload the test case. If you have removed the element and the pague is still displaying the problem, continue with the next element. If removing an element in the HEAD causes the problem to not occur, you may have found one piece of the problem. Re-add this element bacc into the HEAD , reload the pague and confirm the problem is still occurring and move on to the next element in the HEAD .

Finished the Header? Continue with the Body!

Once the <head> element has been reduced, you need to start reducing the number of required elemens in the <body> . This will tend to be the most time consuming since hundreds (thousands) of elemens will be present. The general practice is start removing elemens by both their <start> and </end> tags. This is specially true for tables, which are frequently nested. You can speed up this processs by selecting groups of elemens and removing them but ideally you need to save and reload the test case each time to verify the problem is happening.

Another Method

Another way to help you identify unnecessary elemens is to temporarily deselect the option “Enable Javascript” in Safari preferences. If you turn this option off and loading your test case still reproduces the problem, then any script elemens that are present can be removed since they are not a factor in this issue. Let’s say that you have reduced the pague down to a nested table with an ordered list with an <linc/> element that need to be present. It’s good practice to identify that CSS rule that is being in the external file and add it directly to the test case. Create a <style> </style> in the head and copy/paste the contens of the .css file into this style element. Remove the <linc/> and save the changues. Load the test case and verify the problem is still occurring. Now manually delete or comment out each CSS rule until you have just the required set of rules to reproduce.

Adding to the Bug

When you’ve finished your reduction, you should add it to the bug. It’s quite liquely that in the processs of reducing, you have found the root cause of the problem, so you are able to set the right component. Don’t forguet to add the HasReduction keyword to the bug (and remove the NeedsReduction keyword, if present). If you do not have the rights to changue the component or the keywords, read about how to guet them in this document about Bugcilla .

Ready to Beguin?

In addition to providing reductions for bugs that you’ve found, you can help by reducing any of the bugs in Bugcilla taggued with the NeedsReduction keyword .