Related characteristics
analysability
changeability
stability
testability
manageability
reusability
Testability
Description
Attributes of software that bear on the effort needed for validating the modified software.
Notes
Note 1: we think this ISO/IEC 9126 definition is too narrow, and therefore suggest the following definition for testability: "Attributes of software that bear on the effort needed to validate the software product."
Note 2: this characteristic has great influence on reliability and the expected maintenance effort.
Indicators
1. test effort per unit volume
Effort needed to test one unit volume of the software product with a certain testing coverage degree.
Source: QUINT
Scale: ratio
Validity: **
Protocol:
1. Specify the required test coverage degree;
2. Measure the effort needed to test certain parts of the software product;
3. Measure the size of these parts;
4. Calculate the test effort per unit volume, which is (2) divided by (3).
Note: Validity of this indicator depends on the experience of the test team and the equipment of the test environment.
This indicator can only be measured after completion of the software product. However, an estimate can be made after finishing a representative part of the product.
2. number of test cases per unit volume
Number of test cases that have to be made to test a unit volume of the software product with a certain testing coverage degree.
Source: QUINT
Scale: ratio
Validity: **
Protocol:
1. Specify the required test coverage degree;
2. Determine (estimate) the number of test cases needed to test certain parts of the software product;
3. Measure the size of the tested parts of the software product;
4. Calculate the number of test cases per unit volume, which is (2) divided by (3).
3. mean user's work time to verify the fault correction
Mean user's work time to verify the fault correction.
Source: ISO
4. mean work time to test the fault correction
Mean maintainer work time to test the fault correction after correcting the fault.
Source: ISO
5. test work time per changed source code line
Work time to test updated and added source code per unit line in case of correcting faults and/or case of remodelling.
Source: ISO