function test_xF(grid, xF)
    return grid.xF == xF
end

function test_xC(grid, xC)
    return grid.xC == xC
end

function test_yF(grid::Grid2D, yF)
    return grid.yF == yF
end

function test_yC(grid::Grid2D, yC)
    return grid.yC == yC
end

function xdomain_length(grid, Lx)
    return grid.Lx == Lx
end

function ydomain_length(grid::Grid2D, Ly)
    return grid.Ly == Ly
end
