plot_real_imag(sqrt(x), (x, -3-3j, 3+3j),
    n=100, real=False, imag=False, abs=True, threed=True)
# Expected:
## Plot object containing:
## [0]: complex cartesian surface: sqrt(sqrt(re(x)**2 + im(x)**2)*sin(atan2(im(x), re(x))/2)**2 + sqrt(re(x)**2 + im(x)**2)*cos(atan2(im(x), re(x))/2)**2) for re(x) over (-3.0, 3.0) and im(x) over (-3.0, 3.0)