Yes, it does test I ran the APK through a decompiler, and can see that it is really running the LL test. The apparently low CPU usage can likely be explained by the fact that the app is really inefficient: it uses Java's BigInteger class (which is quite slow in any case), with this at the heart of it: s = s.multiply(s).subtract(BigInteger.valueOf(2L)).mod(mp); This is the LL test, but not the best way to implement it: lots of garbage and unnecessary calculations here. But the app doesn't claim to be anything else. "The code is not optimized."
Fake, deceiving, does not really test. Uses a list of known Mersenne primes. Probably as an array. Uses knowledge that the algorithm is approximately n^2 time completity (without FFT multiplication) and makes the loading bar take longer for higher numbers. You can look at the CPU usage overlay or even a system monitor app and you can see that it is not using any noticeable CPU time. If it were real, it would provide feedback like Prime95 does and would actually tell you the residue. This developer is the scum of the earth. I will be reporting.
Un gran programa para todos los que nos gustan los numeros primos.
Now should work with older versions of android (1.6 or later), and I added as scroll bar to read the whole text.