Add split parameters tests

Needs SciML/ModelingToolkitStandardLibrary.jl#211

Author: YingboMa

test/runtests.jl

@@ -23,6 +23,7 @@ using SafeTestsets, Test
 @safetestset "JumpSystem Test" include("jumpsystem.jl")
 @safetestset "Constraints Test" include("constraints.jl")
 @safetestset "Reduction Test" include("reduction.jl")
+@safetestset "Split Parameters Test" include("split_parameters.jl")
 @safetestset "ODAEProblem Test" include("odaeproblem.jl")
 @safetestset "Components Test" include("components.jl")
 @safetestset "Model Parsing Test" include("model_parsing.jl")

test/split_parameters.jl

@@ -0,0 +1,31 @@
+using ModelingToolkit, Test
+using ModelingToolkitStandardLibrary.Blocks
+using OrdinaryDiffEq
+
+dt = 4e-4
+t_end = 10.0
+time = 0:dt:t_end
+x = @. time^2 + 1.0
+
+@parameters t
+D = Differential(t)
+
+vars = @variables y(t)=1 dy(t)=0 ddy(t)=0
+@named src = SampledData(; data = Float64[], dt)
+@named int = Integrator()
+
+eqs = [y ~ src.output.u
+    D(y) ~ dy
+    D(dy) ~ ddy
+    connect(src.output, int.input)]
+
+@named sys = ODESystem(eqs, t, vars, []; systems = [int, src])
+s = complete(sys)
+sys = structural_simplify(sys)
+
+prob = ODEProblem(sys, [], (0.0, t_end), [s.src.data => x]; split_parameters = true)
+@test prob.p isa Tuple{Vector{Float64}, Vector{Int}, Vector{Vector{Float64}}}
+@time sol = solve(prob, ImplicitEuler());
+prob2 = ODEProblem(sys, [], (0.0, t_end), [s.src.data => x]; to_float = false)
+@test prob2.p isa Vector{Union{Float64, Int64, Vector{Float64}}}
+@time sol2 = solve(prob2, ImplicitEuler());