[pixel shader]
float4 main() : SV_target
{
    float4 ret;
    ret.yxz.yx = float2(0.1, 0.2);
    ret.w.x = 0.3;
    ret.wzyx.zyx.yx.x = 0.4;
    return ret;
}

[test]
draw quad
probe all rgba (0.1, 0.2, 0.4, 0.3)