1. A method for customizing a test instrument, comprising: storing first code for execution by a processor of the test instrument; storing second code for implementation on a programmable hardware element of the test instrument; receiving user input customizing the second code prior to said storing the second code, wherein the user input specifies the adaptive behavior for the test instrument; generating a hardware description for the programmable hardware element based on the user input; wherein, after implementation of the hardware description on the programmable hardware element and during testing of a system under test (SUT) coupled to the test instrument, the test instrument is configured to determine information received from the SUT during testing of the SUT; and wherein operation of the test instrument is automatically modified based on the adaptive behavior specified by the user input and the information received from the SUT during testing of the SUT.