Bugs, Errors, Defects, Faults, Failures – All are indicators of customer dissatisfaction, especially when found in the production environment. With the increasing complexity of the software being developed, it is imperative to catch the high priority bugs before the application goes into production. The purpose of this article is to provide a practical approach of identifying test cases so as to catch maximum bugs before the product goes into production environment.

There are several suggested ways of designing test cases such as Boundary Value Analysis, Equivalence Partitioning, Error guessing (Intuition) etc. However in this article we would learn how test cases can be derived from bugs which have been identified in the existing software.

The article is written in a bug-test-case approach. For every bug, one or more corresponding test cases are defined. The bugs and test cases listed are not specific to any application, but may apply to one or more of the following kinds of applications – Client-Server, Web, Desktop applications and so on.  Majority of the bugs mentioned below are relevant to the Microsoft windows operating system, but some of them are generic in nature.

Let us get started. The contents below are in no particular order:

Bug 1 – A field in a dialog displays the time of a particular event. The time shows incorrectly when viewed in a different time-zone
For applications in which time is displayed, have a test case to verify the display is correct when the time zone is changed to

• GMT

• GMT + n hours

• GMT – m hours

Bug 2 – The information is not correctly displayed when Windows Operating System is installed in a volume other than C:\Windows (esp. true for dual-boot operating systems)

• Install operating system in a different volume and verify the behavior of your application. If there are any logs, are they generated correctly like installation logs, activity logs, database logs etc.?

•  Have operating system installed in one volume and ‘Document and Settings’ folder in another volume. Verify application consistency.

Bug 3* – Open a dialog and click OK button to close the dialog without any changes. When the dialog is reopened, a field in the dialog is now grayed out.

• Test for Zero path – Open and close a dialog without any changes. Reopen the dialog to verify that default values are retained.

• Open a dialog, change the default value to another value and change it back again to default value. Verify the default values are retained

• Open a dialog, enter null values and verify that such scenarios are handled by the application

Bug 4 – Problem with operating system when it has maximum number of volumes like C:,D:…Z:\ on Windows OS containing different file systems – FAT, FAT32, NTFS

• Install your product on different file systems

• Install your product with one component in C:, second in D:, third in E: and so on – all components in separate volumes

Bug 5 – Application crashes when file system is filled to capacity

• File the file system to capacity –disk full condition and force the application to open, close, read/write and modify files and data

Bug 6 – Application fails to install/function or read/write to a mounted volume

• Mount a volume (say E:\) to a folder in an existing volume say C:\. Now try following operations:
  a)     Install your application in the mounted folder
  b)     Read from the mounted folder
  c)     Write data to the mounted folder
  d)     Backup the mounted folder and so on

Bug 7 – Application fails to validate virus infected files

• Test for application functionality with virus files (can be downloaded from eicar.com)

• Test for application functionality with a combination of virus and clean files, virus files compressed along with clean files.

Bug 8* – Space character causes text truncation after the record is saved and reopened

• Test the fields in your User Interface (UI) for space characters. In many instances, developers leave checks for such exceptions – which leads to bugs.

• Test the field in UI for other characters on the keyboard - ~!@#$%^&*()

• Test with some other special characters using ‘charmap’ Windows utility

Bug 9 – Display is incorrect for records which are purged from the database after a certain time period

• Suppose your database grows in size regularly and you have defined purge policies after every say 30 days. Verify after every 30 days when the older records are purged, how the GUI handles that. So if there is an option to see history of the data – how is the purged data being displayed?

Bug 10* – Application crashes on browsing a blank folder

• Verify accessing/browsing blank folders

• Verify your application functionality with deep folders such as 55 levels deep say C:\1\2\3\4\5\6\7\8…

• Verify your application functionality with long path length folders say C:\This is an article on test case and bugs\This is an article on test case and bugs2\...