Ghostbuster Testing Using BBST Foundations Knowledge


This one describes interesting bug and how I used what I learned on BBST Foundations course knowledge to solve it.

Test script in Ruby opens a file with test data. It throw following exception:

No such file or directory @ rb_sysopen

Let’s use comparable tool, windows explorer (an Oracle). File is present. Let’s open it in Chrome. I got following error:

Your file was not found.

It may have been moved or deleted.


BBST Foundations states in lesson 3 Oracles that we always create a model of System Under Test. Here is expanded Testing Model by D. Hoffman:

Copyright © 1998, SQM, LLC.

Copyright © 1998, SQM, LLC.

Files are part of Environmental Inputs. In order to open a file we need to provide file PATH. What is operating system property for my environment?


My previous experience alarmed me that Windows MAX_PATH has length limit of 260 characters. For example Linux has MAX_PATH of 4096 characters.

Solution to this issue was to move files closer to file system root, and on Windows, this is c: drive.

When Ruby tries to open a file, it uses operating system API, and API returned false error message: file not found.

More useful error would be: MAX_PATH exceeded.


BBST provided me blocks of knowledge information that I used when I encounter testing problems. In other words, that course thought me to critically think.

Originally published at tentamen software testing blog.