From the New York Times: Are We Living In A Computer Simulation? Let's Not Find Out.

It lists the standard reasons for thinking we might be in a simulation, then brings up some proposals for testing the hypothesis (for example, the cosmic background radiation might look different in simulations and real universes). But it suggests that we not do that, because if we learn we're in a simulation, that might ruin the simulation and cause the simulators to destroy the universe.

But I think a little more thought suggests we don't have anything to worry about.

In order to notice we had discovered our simulated nature, the simulators would have to have a monitor watching us. We should expect this anyway. Although humans may run some simulations without monitoring them carefully, the simulators have no reason to be equally careless; if they can simulate billions of sentient beings, their labor costs are necessarily near zero. Such a monitor would have complete instantaneous knowledge of everything happening in our universe, and since anyone who can simulate a whole planet must have really good data processing capabilities, it would be able to understand and act upon the entire content of its omniscient sensorium. It would see the fall of each sparrow, record the position of ever atom, have the level of situational awareness that gods could only dream of.

What I'm saying is, it probably reads the New York Times.

That means it knows these experiments are going to happen. If it cares about the results, it can fake them. Assuming for some reason that it messed up designing the cosmic background radiation (why are we assuming this, again?), it can correct that mistake now, or cause the experimental apparatus to report the wrong data, or do one of a million other things that would prevent us from learning we are in a simulation.