Test Levels

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Software Testing-ISTQB ISEB Foundation Guide

In our previous article, we have discussed Software Testing Development Models.

For both types of development, testing plays a significant role. Testing helps to ensure that the work-products are being developed in the right way (verification) and that the product will meet the user needs (validation).

Characteristics of good testing across the development life cycle include:

• Early test design—In the V-model, we saw that test planning begins with the specification documents. This activity is part of the fundamental test process. After test planning, the documents would be analyzed and test cases designed. This approach would ensure that testing starts with the development of the requirements, i.e. a proactive approach to testing is undertaken. As we saw in iterative development, test-driven development may be adopted, pushing testing to the front of the development activity.
• Each work-product is tested—In the V-model, each document on the left is tested by an activity on the right. Each specification document is called the test basis, i.e. it is the basis on which tests are created. In iterative development, each release is tested before moving on to the next.
• Testers are involved in reviewing requirements before they are released—In the V-model, testers would be invited to review all documents from a testing perspective.

The test stages of the V-model are shown. They are often called test levels. The term test level provides an indication of the focus of the testing, and the types of problems it is likely to uncover. The typical levels of testing are:

• Unit (component) testing
• Integration testing
• System testing
• Acceptance testing

Each of these test levels will include tests designed to uncover problems specifically at that stage of development. These levels of testing can be applied to iterative development also. In addition, the levels may change depending on the system. For instance, if the system includes some software developed by external parties, or bought off the shelf, acceptance testing on these may be conducted before testing the system as a whole.

You may follow the complete series of Software Life Cycles articles here:

Software Testing Development Models
Test Levels
Software Testing Types
Maintenance Testing

To see all articles of ISTQB-ISEB Foundation guide, see here:

Software Testing-ISTQB ISEB Foundation Guide