Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove the connector from the gas valve

Measurement:

Test 1:
Measure the resistance between the top and bottom pins on the gas valve.
Expect approximately 7.7 KOhms.
Test 2:
Measure the resistance between the top pin of the gas valve and earth.
Expect open circuit.
Test 3:
Measure the resistance between the bottom pin of the gas valve and earth.
Expect open circuit.