using ITensors,
      Test

@testset "Fermions" begin

  @testset "parity_sign function" begin

    # Full permutations
    p1 = [1,2,3]
    @test ITensors.parity_sign(p1) == +1
    p2 = [2,1,3]
    @test ITensors.parity_sign(p2) == -1
    p3 = [2,3,1]
    @test ITensors.parity_sign(p3) == +1
    p4 = [3,2,1]
    @test ITensors.parity_sign(p4) == -1

    ## Partial permutations
    p5 = [2,7]
    @test ITensors.parity_sign(p5) == +1
    p6 = [5,3]
    @test ITensors.parity_sign(p6) == -1
    p7 = [1,9,3,10]
    @test ITensors.parity_sign(p7) == -1
    p8 = [1,12,9,3,11]
    @test ITensors.parity_sign(p8) == +1

  end

end
