I haven't used any free web hosting since Geocities in the late 90s, but depending on what your needs are there are some paid hosts available very cheaply.
NearlyFreeSpeech offer a pay-for-what-you-actually-use pricing model that can be very cheap for low usage, and they accept very small deposits; they're a little less user-friendly, but if they meet your needs they even continue to perform well for larger/busier sites, although depending on your usage they may end up more expensive than other hosts in those cases.
I'm just not sure that live stress testing on a free host will probably have you on a resource-starved shared server, possibly with some functionality disabled will get you results that are actually meaningful compared to the same code running in a proper environment.