Tuesday, July 15, 2008

Designing Test Cases

Designing Test Cases

A test case is a detailed procedure that fully tests a feature or an aspect of a feature. Whereas the test plan describes what to test, a test case describes how to perform a particular test. You need to develop a test case for each test listed in the test plan.

A test case includes:
  • The purpose of the test.

  • Special hardware requirements, such as a modem.

  • Special software requirements, such as a tool.

  • Specific setup or configuration requirements.

  • A description of how to perform the test.

  • The expected results or success criteria for the test.

Test cases should be written by a team member who understands the function or technology being tested, and each test case should be submitted for peer review.

Organizations take a variety of approaches to documenting test cases; these range from developing detailed, recipe-like steps to writing general descriptions. In detailed test cases, the steps describe exactly how to perform the test. In descriptive test cases, the tester decides at the time of the test how to perform the test and what data to use.

Most organizations prefer detailed test cases because determining pass or fail criteria is usually easier with this type of case. In addition, detailed test cases are reproducible and are easier to automate than descriptive test cases. This is particularly important if you plan to compare the results of tests over time, such as when you are optimizing configurations. Detailed test cases are more time-consuming to develop and maintain. On the other hand, test cases that are open to interpretation are not repeatable and can require debugging, consuming time that would be better spent on testing.

Test Case Design

Test Case ID:
It is unique number given to test case in order to be identified.

Test description:
The description if test case you are going to test.

Revision history:
Each test case has to have its revision history in order to know when and by whom it is created or modified.

Function to be tested:
The name of function to be tested.

It tells in which environment you are testing.

Test Setup:
Anything you need to set up outside of your application for example printers, network and so on.

Test Execution:
It is detailed description of every step of execution.

Expected Results:
The description of what you expect the function to do.

Actual Results:
pass / failed

If pass - What actually happen when you run the test.

If failed - put in description of what you've observed.

Monday, July 14, 2008

Regression testing Introduction

Regression testing is any type of software testing which seeks to uncover regression bugs. Regression bugs occur whenever software functionality that previously worked as desired, stops working or no longer works in the same way that was previously planned. Typically regression bugs occur as an unintended consequence of program changes.

Common methods of regression testing include re-running previously run tests and checking whether previously fixed faults have re-emerged.

Types of Regression

Local - changes introduce new bugs.
  • Unmasked - changes unmask previously existing bugs.
  • Remote - Changing one part breaks another part of the program. For example, Module A writes to a database. Module B reads from the database. If changes to what Module A writes to the database break Module B, it is remote regression.

There's another way to classify regression.

  • New feature regression - changes to code that is new to release 1.1 break other code that is new to release 1.1.
  • Existing feature regression - changes to code that is new to release 1.1 break code that existed in release 1.0.

Uses of Regression Testing

Regression testing can be used not only for testing the correctness of a program, but it is also often used to track the quality of its output. For instance in the design of a compiler, regression testing should track the code size, simulation time and compilation time of the test suite cases.

Recommended Resources
Testing Interview Questions - http://www.coolinterview.com/type.asp
Testing Tools Interview Questions - http://www.coolinterview.com/type.asp
What is Software Testing?- http://en.wikipedia.org/wiki/Software_testing
Software QA & Testing Resource Center- http://www.softwareqatest.com/
Testing Faqs- http://www.testingfaqs.org/