fix contract

Author: ogauthe

src/fusiontensor/fusiontensoraxes.jl

@@ -7,7 +7,7 @@ using GradedArrays:
   dual,
   sector_type,
   trivial
-using TensorAlgebra: BlockedTuple
+using TensorAlgebra: AbstractBlockPermutation, BlockedTuple
 using TensorProducts: ⊗
 using TypeParameterAccessors: type_parameters
 
@@ -79,6 +79,10 @@ for f in [:(getindex), :(iterate)]
   @eval Base.$f(fta::FusionTensorAxes, i) = $f(outer_axes(fta), i)
 end
 
+function Base.getindex(fta::FusionTensorAxes, bp::AbstractBlockPermutation)
+  return FusionTensorAxes(outer_axes(fta)[bp])
+end
+
 Base.copy(fta::FusionTensorAxes) = FusionTensorAxes(copy.(outer_axes(fta)))
 
 Base.deepcopy(fta::FusionTensorAxes) = FusionTensorAxes(deepcopy.(outer_axes(fta)))

test/test_fusiontensoraxes.jl

@@ -67,6 +67,7 @@ end
   @test all(map(r -> space_isequal(r, g2), fta[Block(1)]))
   @test length(fta[Block(2)]) == 2
   @test all(map(r -> space_isequal(r, g2b), fta[Block(2)]))
+  @test length.(fta) == tuplemortar(((2, 2), (2, 2)))
 
   @test blocklength(fta) == 2
   @test blocklengths(fta) == (2, 2)