To test a connector set, note both parts of the connection, the connector set must be tested in a normal circuit application. Measure the voltage drop across the connector and the current in the circuit. Then you can calculate the power on the connector set. Make sure to use true RMS values when measuring AC current and voltage.
Only then can you apply the proper voltage on the connector at the expected current to test the heating of the connector.
As with all connectors, they may also fail due to voltage arcing or excessive current surges causing arc marks which increase the effective resistance of the connector. This is why all real electrical maintenance programs on critical equipment use a thermal imager or temperature device to periodically check the operating temperature of connections and other devices to see if there has been an increase due to impending failure.
As for your actual test. Forget about any resistive load except for the resistance of the connector itself. You will need to make sure that the wiring resistance is at least 10 times less than the connector resistance in order to test it by applying a constant current source of
10 amps. Otherwise the wiring will seriously skew the results by more than 10%.