I have to object to your assertion that theories of evolution (I intentionally use the plural, as many details of its progress and operation are still open areas of research) do not yield testable predictions. In fact, many observations of the natural world in myriad fields of study -- all subsequent to the formulation of evolution -- have been in accord with its predictions. I give an excerpt from a longer post of mine made at The Bonehead Compendium:
In addition, evolutionary theory did make a number of predictions that were born out by subsequent empirical observations. The occurrence of microevolution is one of them. We have also observed speciation in the wild and in the laboratory, in accordance with evolutionary predictions. More precisely, given populations of the same species (i.e. successfully interbreeding) that are then reproductively separated from one another and subjected to different selection pressures, it has been observed that they will fail to interbreed upon reintroduction to one another. This, in turn, means that speciation has occurred. I refer you to paper to the following papers on the yellow monkey flower , fruit flies , and rat worms.
The existence of vestigial organs is also a phenomenon explained by evolution. Indeed, it is also a phenomenon not well explained by ID, as their superfluous nature contradicts any principles of utilitarian design. The hind limbs of whales are some of the best examples of this, and it is likely the case that the human appendix is one such structure.
Comparative embryology also offers observations that are well explained by evolution. The gill-like structures found on the human embryo serve no purpose in embryonic development except to develop into other structures with significantly different morphology. The existence of these structures in the embryos of a vast catalog of other species is also explained. A piscine common ancestry which is manifested during development makes this phenomenon comprehensible.
These observations, and countless others, are made significantly more comprehensible by the application of an evolutionary paradigm.
The full post and the exchange prompting it are available here. I wish I could revise it, as I fired it off pretty quickly and now lament the quality of the writing. I still stand by the argument and the evidence.