Fix tests

Author: mtfishman

ext/BlockSparseArraysTensorAlgebraExt/BlockSparseArraysTensorAlgebraExt.jl

@@ -4,13 +4,21 @@ using BlockArrays: AbstractBlockArray, Block, blocklength, blocks, eachblockaxes
 using BlockSparseArrays: AbstractBlockSparseArray, AbstractBlockSparseMatrix,
     BlockUnitRange, blockrange, blocksparse
 using SparseArraysBase: eachstoredindex
-using TensorAlgebra: TensorAlgebra, BlockedTuple, FusionStyle, matricize, matricize_axes,
+using TensorAlgebra: TensorAlgebra, BlockedTuple, matricize, matricize_axes,
     tensor_product_axis, unmatricize
 
-const BlockReshapeFusion = typeof(FusionStyle(AbstractBlockArray))
+# TODO: Ideally we would use:
+# ```julia
+# const BlockReshapeFusion = typeof(TensorAlgebra.FusionStyle(AbstractBlockArray))
+# ```
+# but that doesn't seem to work, i.e. it sometimes returns `ReshapeFusion`. Maybe it is
+# a world age issue, though note that `@invokelatest` doesn't seem to fix it.
+# For now we just use `Base.get_extension`.
+const BlockReshapeFusion =
+    Base.get_extension(TensorAlgebra, :TensorAlgebraBlockArraysExt).BlockReshapeFusion
 
 function TensorAlgebra.tensor_product_axis(
-        style::BlockReshapeFusion, side::Val{:codomain}, r1::BlockUnitRange, r2::BlockUnitRange
+        style::BlockReshapeFusion, side::Val{:codomain}, r1::BlockUnitRange, r2::BlockUnitRange,
     )
     return tensor_product_blockrange(style, side, r1, r2)
 end