Can I measure induced drag with a simple wind tunnel test?
Yes, by the textbook definition $C_D=C_{D_0}+KC_L^2$.
Your measurement at AoA=0° gives $C_{D_0}$, 500 N.
Your measurement at another AoA=15°, by subtraction, gives $KC_L^2$, the induced drag at that AoA, 200 N.
If measurements at many AoA's yield a consistent $K$ and $C_L$,
then you gain confidence in those values.
If the airfoil is strongly cambered, a better fit to the equation is made if you add another term proportional to $C_L$ (not squared).