Disclosed are ignition source testing systems and methods that utilize a foam with flammable components to indicate the presence of an ignition source on a test article (such as metallic components of a fuel system). Foam is applied to the test article and an energy discharge (such as a simulated lightning strike) is applied to the test article with the foam. The energy discharge may create an ignition source (such as an arc) on the test article that is sufficient to ignite the foam. Test methods comprise determining whether the foam ignited in response to the energy discharge. Test systems comprise the foam, the test article at least partially covered by the foam, and an energy source configured to discharge energy into the test article.