It is the form of functional testing. Special value testing occurs when a tester uses his or her domain knowledge, experience with similar program and information about “soft spots” to dense test case. No guidelines are used other than to use “best engineering judgment”. As a result special value testing is heavily dependent on the abilities of the testing persons.

Cause- effect Graphing Technique

Both boundary value analysis and equivalence partitioning do not explore combination of input circumstances. If there are “n” different input conditions, we will have 2n test cases.

Cause effect graphing is a technique that aids in selecting, in a systematic way, a higher yield set of test cases, if has a beneficial effect in pointing out incompleteness and ambiguities in the specifications.

Process to Derive Test Cases

  1. A cause is a distinct input condition or an equivalence class of input conditions. A effect is an output condition or a system transformation. Identify the causes and effect by reading the specification and then assign a unique number.

  2. The semantic content of the specification is analyzed and transformed into a Boolean graph linking the causes and effects. This the cause effect graph.

  3. The graph is annotated with constraints describing combinations of causes and/or effects that are impossible because of syntactic or environmental constraints.

  4. By methodically tracing state conditions in the graph, the graph is converted into a limited entry decision table. Each column in the table represents a test case.

  5. The columns in the decision table are converted into test case.