Test Design

Definition

Test design is the testing task of designing the testing work products.

Objectives

Test design typically has the following objectives:

• Design the test work products:
  • Test harnesses.
  • Test procedures.
  • Test scripts.
  • Test suites of test cases.
  • Test data.
• Maximize the effectiveness of testing:
  • Maximize the probability of tests causing previously unidentified failures.
  • Minimize the number of test suites and test cases.

Preconditions

Test design can typically begin when the following preconditions hold:

• The initiation phase has begun.
• The test teams are staffed and trained in test design.

Completion Criteria

Test design is typically complete when the following postconditions hold:

• Testing work products have been successfully designed.

Steps

Test design typically involves performing the following steps:

• Identify the test suites.
• Determine the objectives of each test suite.
• Develop the test procedures (for manual tests)
• Determine the test cases necessary to meet the objectives (e.g., completion criteria) of the test suite.
• For each test case, determine and document in the associated test case the:
  • Test preconditions (e.g., object state, software component state, and database contents).
  • Test steps (i.e., test stimuli).
  • Test postconditions (e.g., returned value, object state, database state, exceptions thrown or handled, and messages sent).
  • Test schedule (for system tests)
  • Required resources (for system tests)

Techniques

Test design typically can be performed using the following techniques:

• Testing patterns
• Refactoring

Work Products

Test design typically results in the production of all or part of the following testing work products:

• Documentation:
  • Master test list (identification of tests)
  • Test procedure (outline of test procedure)
• Software:
  • Test harness design
  • Test script design
  • Test suite design
  • Test case design
  • Test data design

Guidelines

• Most of the testing techniques provide guidance on designing test suites of test cases.
• Test design could theoretically be part of the testing activity or part of the design activity. It was placed here because it is more closely thought of as being part of the testing activity, whereas the scope of the design activity is typically thought of as being restricted to the design of the application itself.