15. A method, implemented by a computing device, comprising: providing software being tested; at runtime of the software, injecting one or more additional constraints into the software, the injecting including adding a cast to a type in the software wherein the cast pertains to an issue; executing the software with the added cast for a concrete input; and actively checking for an input that causes the issue, wherein runtime testing is extended by actively checking for the input that causes the issue for program executions of the software that follow a same program path.
15. A method, implemented by a computing device, comprising: providing software being tested; at runtime of the software, injecting one or more additional constraints into the software, the injecting including adding a cast to a type in the software wherein the cast pertains to an issue; executing the software with the added cast for a concrete input; and actively checking for an input that causes the issue, wherein runtime testing is extended by actively checking for the input that causes the issue for program executions of the software that follow a same program path. 18. The method of claim 15 , wherein the issue is selected from at least one of a division by zero, an underflow, and an overflow.