Specification Based Test Design Techniques As Per Istqb Advanced Level Syllabus

Specification-Based Test Design Techniques as per ISTQB Advanced Level Syllabus

by

Yogindernath

Test analysts and technical test analysts lay major attention to design, implementation and execution of tests using various testing techniques. Specification-based techniques are one of such techniques.

Specification-based techniques are popular by more refined names like behavior-based techniques or Black Box test design techniques. These techniques can be used for any level of test activity. These are used by both test analysts and technical test analysts, but exploited mainly by the test analysts.

Code is designed and developed from the software requirement s specifications (SRS) documents being the primary input documents. Likewise specification-based test techniques too are based upon the test conditions & test cases derived from the SRS documents.

We can make our specifications that can be in the form of text documents, pictures, models, compilation of features, or any other document which could help us in understanding as to what we expect from the software & how it is going to accomplish that.

Test coverage is represented by the percentage of the specified items addressed by the designed tests. Coverage of all the specified items does not necessarily indicate complete test coverage, but it does indicate that we have addressed what was specified. For further coverage, we may need to look for additional information.

ISTQB Advanced Level syllabus addresses following seven types of specification-based techniques

1) Equivalence Partitioning:

Brief Description: It involves grouping of test conditions into various partitions, which are handled in the same way.

Coverage Criteria: Number of Coverage Partitions / Total No. of Partitions

2) Boundary Value Analysis (BVA):

Brief Description: It involves defining boundaries of the partitions & testing for them thereafter.

Coverage Criteria: Number of Distinct Boundary Values covered / Total No. of Boundary Values

3) Decision table testing / cause-effect graphing:

Brief Description: It involves defining & testing for different combinations of conditions.

Coverage Criteria: Number of combinations of conditions covered / Maximum No. of combinations of conditions

4) State transition Tables:

Brief Description: It involves Identification of all types of valid states & transitions, which need to be tested.

Coverage Criteria: For single transitions, the coverage metrics is the percentage of all valid transitions exercised during test. This is known as 0-switch coverage. For n-transitions the coverage measure is the percentage of all valid sequences of n-transitions exercised during the test. This is known as (n-1) switch coverage

5) All pair testing / Orthogonal Array Testing:

Brief Description: It involves Identification of various combinations of configurations that need to be tested.

6) Classification Tree Method:

Brief Description: It involves the use of graphical notations to describe the classes or test conditions and combinations handled by the test cases.

Coverage Criteria: It depends upon the technique applied, e.g. pair wise is distinct from classification trees.

7) Use Case Testing:

Brief Description: It involves Identification of various usage scenarios & then testing accordingly.

Coverage Criteria: No formal criteria apply.

Sometimes one or more of these techniques are combined to create our tests. For example, the conditions identified in a decision table might be subjected to equivalence partitioning to discover multiple ways in which a condition might be satisfied. Tests would then cover not only every combination of conditions, but also, for those conditions which are partitioned, additional tests would be generated to cover the equivalence partitions.

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Specification-Based Test Design Techniques as per ISTQB Advanced Level Syllabus