add allocation test.

Author: N5N3

test/runtests.jl

@@ -1229,6 +1229,12 @@ Base.BroadcastStyle(::Broadcast.ArrayStyle{MyArray2}, S::Broadcast.DefaultArrayS
         @test length(tested_style) == 4
     end
 
+    @testset "allocation test" begin
+        a = StructArray{ComplexF64}(undef, 1)
+        allocated(a) = @allocated  a .+ 1
+        @test allocated(a) == 2allocated(a.re)
+    end
+
     @testset "StructStaticArray" begin
         bclog(s) = log.(s)
         test_allocated(f, s) = @test (@allocated f(s)) == 0