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84 DUBINSKY, HAZZAN, TALBY, AND KEREN
Figure 6.8 Test Steps and Scenarios per Logic- and Keyword-based Complexity

Test Steps per Entities’ Logic Complexity
20

16

12

8

4

0
Feb Mar Apr May Jun Jul Aug Sep
P A

Test Steps per Entities’ Keyword Complexity
20

16

12
8

4

0
Feb Mar Apr May Jun Jul Aug Sep
P A
The number of test scenarios versus size in Figure 6.7 (bottom) indicates a similar picture. The
plan-driven project is stable over time, while the agile project changes considerably during the
examined period, stabilizing in the last three measured months at a value that is on average 2.3
times higher than that of the plan-driven project.
According to these results, the agile project is more thoroughly tested than the plan-driven project.
This can be attributed mainly to the development process. In the agile project, a task is not consid-
ered complete until its tests are written and have been passed; further, it is the responsibility of the
developer who coded a task to write and run the tests. This ensures that tests are written for all tasks,
and not just for high-priority tasks, as has happened during high-pressure periods in the plan-driven
project. In the plan-driven project, if the QA team lags behind the development team for any reason
(insufficient personnel, new features that take more time to test than to code, other urgent work, etc.),
the developers keep coding features and the lag increases further. This quickly leads to prioritizing
test writing and focusing on high-risk features. In contrast, in an agile project, the QA personnel are
part of the development team, and developers are responsible for writing tests as well. In this way,
the team does not move on with development before testing is completed.