Add test

Author: michel2323

test/indexing.jl

@@ -18,3 +18,48 @@ using oneAPI
     mask = oneArray(Bool[true, false, true, false, false, true])
     @test Array(data[mask]) == collect(1:6)[findall(Bool[true, false, true, false, false, true])]
 end
+
+@testset "CartesianIndices with mapreduce" begin
+    # Test for bug fix: mapreduce with CartesianIndices and tuple reduction
+    # Previously failed due to SPIR-V codegen issues with nested insertvalue instructions
+    # when combining tuples of (bool, CartesianIndex) in reduction operations.
+    # The fix involved properly handling nested struct insertions in SPIR-V codegen.
+
+    # Test that we can zip CartesianIndices with array values in a mapreduce
+    # This tests the fix for nested tuple operations in SPIR-V codegen
+
+    # Simple test: sum of values while tracking indices
+    x = oneArray(ones(Int, 2, 2))
+    indices = CartesianIndices((2, 2))
+
+    # Map to tuple of (value, index), then reduce by summing the values
+    result = mapreduce(tuple, (t1, t2) -> (t1[1] + t2[1], t1[2]), x, indices;
+                       init = (0, CartesianIndex(0, 0)))
+    @test result[1] == 4  # sum of four 1s
+
+    # Test with 1D array
+    y = oneArray(ones(Int, 4))
+    indices_1d = CartesianIndices((4,))
+    result_1d = mapreduce(tuple, (t1, t2) -> (t1[1] + t2[1], t1[2]), y, indices_1d;
+                          init = (0, CartesianIndex(0,)))
+    @test result_1d[1] == 4
+
+    # Test with boolean array and index comparison (closer to original failure case)
+    # This pattern is similar to what findfirst would use internally
+    z = oneArray([false, true, false, true])
+    indices_z = CartesianIndices((4,))
+    result_z = mapreduce(tuple,
+                         (t1, t2) -> begin
+                             (found1, idx1), (found2, idx2) = t1, t2
+                             # Return the first found index (smallest index if both found)
+                             if found1
+                                 return (found1, idx1)
+                             else
+                                 return (found2, idx2)
+                             end
+                         end,
+                         z, indices_z;
+                         init = (false, CartesianIndex(0,)))
+    @test result_z[1] == true  # Found a true value
+    @test result_z[2] == CartesianIndex(2,)  # First true is at index 2
+end