A testing method is provided which includes verifying at least one external signal path of an electronic package environment by testing an input/output (I/O) circuit of an integrated circuit of the electronic package environment with a logic built-in self-test (LBIST) of the integrated circuit, wherein the external signal path being verified is electrically coupled to the tested I/O circuit. A result of verifying of the at least one external signal path is manifested in the integrated circuit's signature, which characterizes a response of the I/O circuit to the LBIST. In another aspect, the verifying of the at least one external signal path includes concurrently testing another I/O circuit of another integrated circuit, which is also electrically coupled to the external signal path.