1. A computer-implemented method performed by a processor, the method comprising: based on a test generation input that defines a plurality of requirements automatically determining a mutated test generation input, wherein the mutated test generation input defining a mutated requirement which is absent from the test generation input, wherein the mutated requirement is based on a requirement of the plurality of requirements and contradicts, at least in part, the plurality of requirements; and generating one or more test-cases based on the mutated test generation input, whereby the one or more test-cases violate at least one requirement of the test generation input.