As a best-practice asserts should be enabled in dev/test environment. Asserts can be enabled by adding the following flag to MAVEN_OPTS. The ellipsis(…) at the end of each namespace (NS) means that anything under that. If there is any other NS used in Cloudstack please add that to the list as well.
Use asserts wherever it is appropriate (for e.g. private methods which assumes certain things about the inputs). Also if there are obsolete ones please review and remove.