it("should all others to themselves", () => {
expect(flip_side(Side.None)).to.equal(Side.None)
expect(flip_side(Side.BottomTop)).to.equal(Side.BottomTop)
expect(flip_side(Side.LeftRightBottomTop)).to.equal(Side.LeftRightBottomTop)
})
it("should flip top to bottom", () => {
expect(flip_side(Side.Top)).to.equal(Side.Bottom)
})
it("should flip bottom to top", () => {
expect(flip_side(Side.Bottom)).to.equal(Side.Top)
})
it("should flip right to left", () => {
expect(flip_side(Side.Right)).to.equal(Side.Left)
})