using FeynmanDiagramGenerator

import FeynmanDiagramGenerator.EmptyTree
import FeynmanDiagramGenerator.Subtree
import FeynmanDiagramGenerator.leaves
import FeynmanDiagramGenerator.ForestIterator

@testset "Number of leaves" begin
    @test leaves(EmptyTree()) == 1
    @test leaves(Subtree(EmptyTree(), EmptyTree())) == 2
    @test leaves(Subtree(EmptyTree(), Subtree(EmptyTree(), EmptyTree()))) == 3
end

@testset "Number of Forests" begin
    @test_throws AssertionError Forest(0)
    @test_throws AssertionError ForestIterator(0)

    groundtruth_lengths = [1, 1, 1, 2, 3, 6, 11, 23, 46, 98, 207, 451, 983, 2179, 4850, 10905, 24631, 56011, 127912, 293547]

    @testset "Forest with $i leaves" for i in 1:20
        @test length([t for t in Forest(i)]) == groundtruth_lengths[i]
        for t in Forest(i)
            @test leaves(t) == i
        end
    end
end