Methods of testing a user design implemented in a programmable integrated
circuit (IC). The programmable IC is programmed with a first test design
that includes the user design and a first test circuit, and a first test
pattern is run. The programmable IC is then programmed with a second test
design that includes the user design and a second test circuit, and a
second test pattern is run. If one of the test patterns fails and the
other passes, the programmable IC passes the test sequence. Because one
of the test patterns passed, the error in the other test pattern must
have occurred in the test circuit, which is not necessary for the
functioning of the user design in the programmable IC. Thus, the success
of one test pattern shows that the flawed resource is not included in the
portion of the programmable IC utilized for implementing the user design.