Update hierarchical_initialization_eqs.jl

Author: ChrisRackauckas

test/hierarchical_initialization_eqs.jl

@@ -142,6 +142,6 @@ syslist = ModelingToolkit.get_systems(model)
 u0 = []
 prob = ODEProblem(structural_simplify(model), u0, (0.0, 10.0))
 sol = solve(prob, Rodas5P())
-@test length(sol[end]) == 2
+@test length(sol.u[end]) == 2
 @test length(equations(prob.f.initializeprob.f.sys)) == 0
 @test length(unknowns(prob.f.initializeprob.f.sys)) == 0