OCCT

box b1 0 0 0 1 1 1
box b2 2 0 0 1 1 1
vclear
vinit View1
vviewparams -scale 404 -proj 0.8 -0.16 0.5 -up -0.4 0.4 0.8 -at 1.5 0.5 0.5
vselfilter -clear
vselprops -pickStrategy first
vdisplay -dispMode 1 -highMode 1 b1 b2
vfit

vselmode b1 4 1
vmoveto 220 220
if { [vreadpixel 220 220 rgb name] != "TURQUOISE2" } { puts "Error: box b2 should be highlighted" }

vselfilter -type FACE
vmoveto 0 0
vmoveto 220 220
if { [vreadpixel 150 150 rgb name] != "CYAN" } { puts "Error: face of box b1 should be highlighted" }

vselprops -pickStrategy topmost
vmoveto 0 0
vmoveto 220 220
if { [vreadpixel 150 150 rgb name] == "CYAN" } { puts "Error: face of box b1 should NOT be highlighted" }

vmoveto 150 150
if { [vreadpixel 150 150 rgb name] != "CYAN" } { puts "Error: face of box b1 should be highlighted" }