In this paper, we study the problem of testing Intrusion Detection Systems (IDS) in Mobile Ad hoc Networks (MANET). Testing is achieved by simulating different measurements. We modify the testing measurements of infrastructure-based networks to be compatible with the characteristics of MANET. Moreover, we add some new features and their associated measurements that we believe important for testing new proposed IDS. The modified measurements with the new added ones form a set of measurements that will be used throughout the testing process. To the best of our knowledge, there has not been any work done for testing IDS in MANET. Simulators are the most common tools used for testing the IDS. Therefore, we add some precautions for choosing a simulator and a list of available simulators. The precautions will help researchers to test the measurements efficiently and the list of simulators will guide them to select one according to their needs. Finally, we present some input parameter precautions that help on having more trustworthy testing results.