Round-trip tests

Author: YingboMa

src/systems/nonlinear/nonlinearsystem.jl

@@ -308,3 +308,10 @@ function flatten(sys::NonlinearSystem)
                               )
     end
 end
+
+function Base.:(==)(sys1::NonlinearSystem, sys2::NonlinearSystem)
+    _eq_unordered(get_eqs(sys1), get_eqs(sys2)) &&
+    _eq_unordered(get_states(sys1), get_states(sys2)) &&
+    _eq_unordered(get_ps(sys1), get_ps(sys2)) &&
+    all(s1 == s2 for (s1, s2) in zip(get_systems(sys1), get_systems(sys2)))
+end

test/nonlinearsystem.jl

@@ -21,7 +21,8 @@ end
 eqs = [0 ~ σ*(y-x),
        0 ~ x*(ρ-z)-y,
        0 ~ x*y - β*z]
-ns = NonlinearSystem(eqs, [x,y,z], [σ,ρ,β])
+ns = NonlinearSystem(eqs, [x,y,z], [σ,ρ,β], defaults = Dict(x => 2))
+@test eval(system2expr(ns)) == ns
 test_nlsys_inference("standard", ns, (x, y, z), (σ, ρ, β))
 @test begin
     f = eval(generate_function(ns, [x,y,z], [σ,ρ,β])[2])

test/odesystem.jl

@@ -17,8 +17,8 @@ eqs = [D(x) ~ σ*(y-x),
        D(z) ~ x*y - β*z]
 
 ModelingToolkit.toexpr.(eqs)[1]
-:(derivative(x(t), t) = σ * (y(t) - x(t))).args
-de = ODESystem(eqs)
+de = ODESystem(eqs; defaults=Dict(x => 1))
+@test eval(system2expr(sys)) == sys
 
 generate_function(de)