When was the first full-scale thermonuclear test?

Theving, thermonuclear refers to fusion bombs, Hiroshima and Nagasaki were 'regular' fission bombs

We are going to really regret that one day. Probably.

Was they're not a test before they drop the bomb on Hiroshima?

Semantics. An A-bomb was "hot" with radiation, but an H-bomb emitted much more heat/energy like the sun.