If you think about all the different criteria we studied, we can draw some relations about them. For example:

• If you achieve 100% decision coverage, you also achieved 100% line coverage.
• If you achieve 100% path coverage, you also achieved 100% decision coverage.

And etc. We call this relations: strategy subsumption. More formally: Strategy X subsumes strategy Y if all elements that Y exercises are also exercised by X.

In the figure below, we show a simplified diagram that exemplifies how one strategy subsumes the next.

Although some apparently are better than the other, research has no conclusive results on which ones are more effective when it comes to bug-finding.

Further reading:

• Test criteria subsumption. Georgia Tech. https://www.youtube.com/watch?v=pZ7J-zw3TSw.