Testing av_spherical_alloc()
alloc: OK, size>0=yes, default projection=4
alloc (no size): OK

Testing av_spherical_projection_name()
projection 0: equirectangular
projection 1: cubemap
projection 2: tiled equirectangular
projection 3: half equirectangular
projection 4: rectilinear
projection 5: fisheye
projection 6: parametric immersive
out of range: unknown

Testing av_spherical_from_name()
equirectangular: 0
cubemap: 1
tiled equirectangular: 2
half equirectangular: 3
rectilinear: 4
fisheye: 5
parametric immersive: 6
nonexistent: -1

Testing projection name round-trip
roundtrip 0 (equirectangular): OK
roundtrip 1 (cubemap): OK
roundtrip 2 (tiled equirectangular): OK
roundtrip 3 (half equirectangular): OK
roundtrip 4 (rectilinear): OK
roundtrip 5 (fisheye): OK
roundtrip 6 (parametric immersive): OK

Testing av_spherical_tile_bounds()
projection: tiled equirectangular
full frame: left=0 top=0 right=0 bottom=0
quarter top-left: left=0 top=0 right=959 bottom=539
centered: left=480 top=270 right=479 bottom=269