cranks but no spark at coil

Ok ECU hooked up, key on, ground -ve coil at battery -ve, and coil tower wire, gives me NADA.
Exact same test with ECU unhooked and I get spark with coil -ve wire to -ve battery BUT again nothing at coil tower wire.
Im thinking ECU is toast. What do you think?
ECU is approx 3 years old and visually looks good.
Is there another test to verify its pooched?