Test run execution gives success message even if the test plan depends on a plugin that is not installed

Environment:

Windows 10, 64-bit

OpenTAP 9.7.0

Demonstration is not installed

Steps to reproduce:

1. Run attached testplan containing a Sine step using tap run sine_9.TapPlan
2. Notice that the plan run ends successfully
3. Notice that the test run mentions the absence of the Demonstration plugin

Actual result:

The test plan run is completed successfully even though the only step in the testplan cannot be loaded

Expected result:

The test plan should result in a failed run

Other remarks:

--via Lucian Coste