diff --git a/src/convert.jl b/src/convert.jl
index 1111452c..d80288f2 100644
--- a/src/convert.jl
+++ b/src/convert.jl
@@ -79,6 +79,7 @@ convert_to_pm_type(::Type{<:AbstractSparseMatrix{<:Union{Bool, CxxWrap.CxxBool}}
 convert_to_pm_type(::Type{<:Union{AbstractSparseVector, SparseVector}}) = SparseVector
 convert_to_pm_type(::Type{<:Array}) = Array
 convert_to_pm_type(::Type{<:Union{Pair, <:StdPair}}) = StdPair
+convert_to_pm_type(::Type{<:Graph{T}}) where T<:Union{Directed,Undirected} = Graph{T}
 # convert_to_pm_type(::Type{<:Union{AbstractSet, Set}}) = Set
 
 # specific converts for container types we wrap:
diff --git a/test/graphs.jl b/test/graphs.jl
new file mode 100644
index 00000000..d181635a
--- /dev/null
+++ b/test/graphs.jl
@@ -0,0 +1,30 @@
+@testset "Polymake.Graph" begin
+    IntTypes = [Int64]
+
+    @testset "constructors" begin
+        c = Polymake.polytope.cube(3)
+        eg = c.GRAPH.ADJACENCY
+        @test Polymake.nv(eg) == 8
+        @test Polymake.ne(eg) == 12
+        g = Polymake.Graph{Polymake.Directed}(5)
+        @test Polymake.nv(g) == 5
+        @test Polymake.ne(g) == 0
+    end
+
+    @testset "manipulating edges and vertices" begin
+        g = Polymake.Graph{Polymake.Directed}(5)
+        Polymake._add_edge(g, 0, 1)
+        @test Polymake.ne(g) == 1
+        @test Polymake._has_edge(g, 0, 1)
+        @test !Polymake._has_edge(g, 1, 0)
+        @test !Polymake._has_vertex(g, 5)
+        Polymake._add_vertex(g)
+        @test Polymake._has_vertex(g, 5)
+        Polymake._rem_vertex(g, 5)
+        @test !Polymake._has_vertex(g, 5)
+        Polymake._rem_edge(g, 0, 1)
+        @test !Polymake._has_edge(g, 0, 1)
+    end
+
+end
+
diff --git a/test/perlobj.jl b/test/perlobj.jl
index 6b1001f8..784bc334 100644
--- a/test/perlobj.jl
+++ b/test/perlobj.jl
@@ -241,6 +241,37 @@
         @test p.LP.LINEAR_OBJECTIVE == x.LP.LINEAR_OBJECTIVE
     end
 
+    @testset "multiple subobjects" begin
+        p = polytope.Polytope( INEQUALITIES=[1 1 -1; -1 0 1; 7 -1 -1] )
+        lp1 = polytope.LinearProgram(LINEAR_OBJECTIVE=[0,1,0])
+        lp2 = polytope.LinearProgram(LINEAR_OBJECTIVE=[0,0,1])
+        lp3 = polytope.LinearProgram(LINEAR_OBJECTIVE=[0,2,1])
+        p.LP = lp1
+        Polymake.add(p,"LP",lp2)
+        Polymake.add(p,"LP","third",lp3)
+        @test Polymake._lookup_multi(p,"LP") isa Polymake.Array{Polymake.BigObject}
+        @test length(Polymake._lookup_multi(p,"LP")) == 3
+        @test Polymake._lookup_multi(p,"LP","third").LINEAR_OBJECTIVE == lp3.LINEAR_OBJECTIVE
+        @test Polymake._lookup_multi(p,"LP",1).LINEAR_OBJECTIVE == lp2.LINEAR_OBJECTIVE
+        @test p.LP.LINEAR_OBJECTIVE == lp1.LINEAR_OBJECTIVE
+        @test_throws ErrorException Polymake._lookup_multi(p,"LP",3)
+        @test_throws ErrorException Polymake._lookup_multi(p,"LP","nonexisting")
+    end
+
+    @testset "bigobject array" begin
+        c = polytope.cube(3)
+        c_type = Polymake.bigobject_type(c)
+        @test Polymake.Array{Polymake.BigObject}(c_type,2) isa Polymake.Array{Polymake.BigObject}
+        arr = Polymake.Array{Polymake.BigObject}(c_type,2)
+        @test length(arr) == 2
+        arr[1] = c
+        arr[2] = polytope.simplex(2)
+        @test arr[1] isa Polymake.BigObject
+        @test arr[2] isa Polymake.BigObject
+        @test arr[1].N_VERTICES == 8
+    end
+
+
     @testset "toplevel visual" begin
         @test visual(polytope.cube(3)) isa Polymake.Visual
     end
diff --git a/test/runtests.jl b/test/runtests.jl
index 1c9373df..2df3c769 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -28,6 +28,7 @@ struct MyInt x::Int end # needed in test/convert.jl
     include("pairs.jl")
     include("lists.jl")
     include("map.jl")
+    include("graphs.jl")
     if get(ENV, "POLYDB_TEST_URI", "") != ""
         include("polydb.jl")
     end