Some Metrics for Software Testing

Functional Test Coverage Metric

Function Test Coverage Metric- It can be used to measure test coverage prior to software delivery. It provides a measure of the percentage of the software tested at any point during testing.

It is calculated as follows:

Function Test Coverage = FE/FT Where,

FE is the number of test requirements that are covered by test cases that were executed against the software

FT is the total number of test requirements.

Software Maturity Metric

Software Maturity Index is that which can be used to determine the readiness for release of a software system. This index is especially useful for assessing release readiness when changes, additions, or deletions are made to existing software systems. It is calculated as follows:

SMI = Mt – ( Fa + Fc + Fd)/Mt, Where

SMI – is the Software Maturity Index value

Mt – is the number of software functions/modules in the current release

Fc – is the number of functions/modules that contain changes from the previous release

Fa – is the number of functions/modules that contain additions to the previous release

Fd – is the number of functions/modules that are deleted from the previous release.

Reliability Metrics:

Reliability is calculated as follows:

Reliability = 1 – Number of errors (actual or predicted)/Total number of lines of executable code

This reliability value is calculated for the number of errors during a specified time interval. Three other metrics can be calculated during extended testing or after the system is in production. They are:

MTTFF (Mean Time to First Failure)‏

MTTFF = The number of time intervals the system is operable until its first failure (functional failure only).

MTBF (Mean Time Between Failures)‏

MTBF = Sum of the time intervals the system is operable

MTTR (Mean Time To Repair)

MTTR = sum of the time intervals required to repair the system The number of repairs during the time period.