Software Testing - Software Testing Basics

Verification is static type of s/w testing. It means code is not executed. The product is evaluated by going through the code. Types of verification are:

1. Walkthrough: Walkthroughs are informal, initiated by the author of the s/w product to a colleague for assistance in locating defects or suggestions for improvements. They are usually unplanned. Author explains the product; colleague comes out with observations and author notes down relevant points and takes corrective actions.
2. Inspection: Inspection is a thorough word-by-word checking of a software product with the intention of Locating defects, Confirming traceability of relevant requirements etc.

The following figure shows pictorially how test documents span across the software development lifecycle. The following discusses the specific testing documents in the lifecycle:

• Central/Project test plan: This is the main test plan which outlines the complete test strategy of the software project. This document should be prepared before the start of the project and is used until the end of the software development lifecycle.
• Acceptance test plan: This test plan is normally prepared with the end customer. This document commences during the requirement phase and is completed at final delivery.
• System test plan: This test plan starts during the design phase and proceeds until the end of the project.
• Integration and unit test plan: Both of these test plans start during the execution phase and continue until the final delivery.

Normally black box test cases are written first and white box test cases later. In order to write black box test cases we need the requirement document and, design or project plan. All these documents are easily available at the initial start of the project. White box test cases cannot be started in the initial phase of the project because they need more architecture clarity which is not available at the start of the project. So normally white box test cases are written after black box test cases are written.

Black box test cases do not require system understanding but white box testing needs more structural understanding. And structural understanding is clearer i00n the later part of project, i.e., while executing or designing. For black box testing you need to only analyze from the functional perspective which is easily available from a simple requirement document.

Unit testing - Testing performed on a single, stand-alone module or unit of code.

Integration Tests - Testing performed on groups of modules to ensure that data and control are passed properly between modules.

System testing - Testing a predetermined combination of tests that, when executed successfully meets requirements.

Acceptance testing - Testing to ensure that the system meets the needs of the organization and the end user or customer (i.e., validates that the right system was built).