+1 for testing it out on-camera. Test at f/1.4, f/2, f/4, f/8 for focus issues like front/back focus, decentering, etc.
due to the shallow DoF when @ f/1.4, it's best to always test from a tripod, or use a very fast shutter speed if handheld, to minimize camera shake affecting your results.
You can use the focus chart from pg 18 of this PDF to check focus issues -- It's best to do this test from a tripod.
Since you mentioned indoors shots, you might also consider the new canon 24mm pancake lens too - excellent IQ, decently wide aperture, and decent autofocus in a tiny, affordable package and on the 70D that effective FL (~38mm, vs, the sigma @ 48mm) might be wide enough.