Some tests?

You can try use these tests:
4999 12832 ->2455.1680336
5000 12345 ->2490.9210000
4987 9999 ->50.7443353
1234 3456 ->394.1183144
2976 6547 ->952.8800403
3487 8000 ->1448.9340407
4955 11111 ->1820.5574168
456 968 ->99.1228070
43 123 ->10.4651163
1 2 ->1
4 9 ->2.2500000
3 9 ->0
2 5 ->1.5
2 4 ->1
4399 13013 ->352.6492385
4321 9923 ->1803.1751909
4001 10500 ->1877.1534616
4000 10001 ->2000.4992500
4000 10000 ->2000.5000000
4123 9999 ->2015.9083192