getindex tests
A = 5×3×4 Tensor{SparseListLevel{Int32, Vector{Int32}, Vector{Int32}, DenseLevel{Int32, SparseListLevel{Int32, Vector{Int32}, Vector{Int32}, ElementLevel{0.0, Float64, Int32, Vector{Float64}}}}}}:
[:, :, 1] =
 0.0   0.0   0.0
 1.01  0.0   6.06
 2.02  3.03  7.07
 0.0   4.04  0.0
 0.0   5.05  0.0

[:, :, 2] =
  8.08   0.0    0.0
  0.0   12.12  14.14
  9.09   0.0    0.0
 10.1   13.13  15.15
 11.11   0.0   16.16

[:, :, 3] =
  0.0   20.2    0.0
 17.17   0.0   24.24
 18.18  21.21  25.25
  0.0   22.22  26.26
 19.19  23.23   0.0

[:, :, 4] =
 0.0   0.0   28.28
 0.0  27.27  29.29
 0.0   0.0   30.3
 0.0   0.0    0.0
 0.0   0.0    0.0
A[1,2,3] = 20.2
A[1,1,1] = 0.0
A[1,Colon(),3] = 3 Tensor{SparseDictLevel{Int32, Vector{Int32}, Vector{Int32}, Vector{Int32}, Dict{Tuple{Int32, Int32}, Int32}, Vector{Int32}, ElementLevel{0.0, Float64, Int32, Vector{Float64}}}}:
  0.0
 20.2
  0.0
A[Colon(),1,3] = 5 Tensor{SparseDictLevel{Int32, Vector{Int32}, Vector{Int32}, Vector{Int32}, Dict{Tuple{Int32, Int32}, Int32}, Vector{Int32}, ElementLevel{0.0, Float64, Int32, Vector{Float64}}}}:
  0.0
 17.17
 18.18
  0.0
 19.19
A[Colon(),Colon(),3] = 5×3 Tensor{SparseDictLevel{Int32, Vector{Int32}, Vector{Int32}, Vector{Int32}, Dict{Tuple{Int32, Int32}, Int32}, Vector{Int32}, SparseDictLevel{Int32, Vector{Int32}, Vector{Int32}, Vector{Int32}, Dict{Tuple{Int32, Int32}, Int32}, Vector{Int32}, ElementLevel{0.0, Float64, Int32, Vector{Float64}}}}}:
  0.0   20.2    0.0
 17.17   0.0   24.24
 18.18  21.21  25.25
  0.0   22.22  26.26
 19.19  23.23   0.0
A[Colon(),Colon(),Colon()] = 5×3×4 Tensor{SparseDictLevel{Int32, Vector{Int32}, Vector{Int32}, Vector{Int32}, Dict{Tuple{Int32, Int32}, Int32}, Vector{Int32}, DenseLevel{Int32, SparseDictLevel{Int32, Vector{Int32}, Vector{Int32}, Vector{Int32}, Dict{Tuple{Int32, Int32}, Int32}, Vector{Int32}, ElementLevel{0.0, Float64, Int32, Vector{Float64}}}}}}:
[:, :, 1] =
 0.0   0.0   0.0
 1.01  0.0   6.06
 2.02  3.03  7.07
 0.0   4.04  0.0
 0.0   5.05  0.0

[:, :, 2] =
  8.08   0.0    0.0
  0.0   12.12  14.14
  9.09   0.0    0.0
 10.1   13.13  15.15
 11.11   0.0   16.16

[:, :, 3] =
  0.0   20.2    0.0
 17.17   0.0   24.24
 18.18  21.21  25.25
  0.0   22.22  26.26
 19.19  23.23   0.0

[:, :, 4] =
 0.0   0.0   28.28
 0.0  27.27  29.29
 0.0   0.0   30.3
 0.0   0.0    0.0
 0.0   0.0    0.0

