Nesting tests

Author: YingboMa

test/components.jl

@@ -47,3 +47,11 @@ sol = solve(prob, Rodas4())
 
 prob = ODAEProblem(sys, u0, (0, 10.0))
 sol = solve(prob, Tsit5())
+
+@variables t x1(t) x2(t) x3(t) x4(t)
+D = Differential(t)
+@named sys1_inner = ODESystem([D(x1) ~ x1], t)
+@named sys1_partial = compose(ODESystem([D(x2) ~ x2], t; name=:foo), sys1_inner)
+@named sys1 = extend(ODESystem([D(x3) ~ x3], t; name=:foo), sys1_partial)
+@named sys2 = compose(ODESystem([D(x4) ~ x4], t; name=:foo), sys1)
+@test_nowarn sys2.sys1.sys1_inner.x1 # test the correct nesting