Where should I enter the pattern when instructed to report a 2-mile left base? Say I'm flying heading 275 and am headed in to land on runway 16 at a towered airport in Class D airspace. I'm 8 miles to the east and have been cleared: "report 2 mile left base runway 16". Should I go for a standard 45 degree traffic pattern entry to downwind at midfield or should I fly straight to the base and report when 2 miles east of the runway?

In this case I went straight for the base and reported and didn't get yelled at by the controller but I'm curious what the correct thing to do is in this situation.

I'm not asking what a 2 mile base is, I'm asking where I should enter the pattern if instructed to report on 2 mile base.
I'm assuming you're more interested in the base-or-downwind question rather than the where-is-the-2-mile-base question.

Theoretically you're supposed to fly the published procedure unless told otherwise. In this case the procedure would probably be a standard traffic pattern.

Being told to 'report' means only that, you should report it when you're there.

This is not to be confused with the (in my experience) more common instruction "Enter and report a 2 mile base for runway 16", in which case you head for the base and not the downwind, and you report it when you get there. To argue ad absurdum, the clearance "Cleared touch and go, after the touch and go, make left traffic, report mid-field downwind" doesn't mean you should head straight for the downwind.

As always, when in doubt, ask.