The current simulator provides a way to test various Cloudstack features without using actual resources. But its current capabilities are limited since it only allows success response for all agent commands and some ability to introduce delays. I am proposing some enhancements to the simulator [1] based on which test developers can write end-to-end tests for scenarios which were earlier not possible. Some examples would be VM deployment failure (due to storage/network failure), VM deployment retry logic, user VM HA etc.
In the current set of automation tests mostly positive scenarios are tested as it is very complex to test negative scenarios with real hardware. With the ability to simulate failure, negative scenarios can be tested in an effective manner. Negative test scenarios will also help in improving the overall code coverage of the tests. Please share your feedback/comments. Thanks, Koushik [1] https://cwiki.apache.org/confluence/display/CLOUDSTACK/Simulator+enhancements