Abstract: According to an exemplary embodiment of the inventive test method, heat is externally applied to an electrochemical “trigger” test cell via a heating element that receives electrical current from a power supply that is characterized by approximately the same impedance as the trigger test cell. For instance, the power supply and the trigger cell can be same or similar cells. The trigger test cell is proximate “propagation-vulnerable” test cells in a cell pack. Because of the impedance-matching between the power supply and the trigger test cell, the ensuing propagative behavior is at least substantially attributable to the short-circuit current failure of the trigger cell as brought about by the externally applied heat. The energy and/or power characterizing the power supply's current at least approximately equates to the energy and/or power characterizing the trigger test cell's short circuit current. Exemplary inventive testing is propitiously representative of real-world propagative failure events.