Add tests

Author: YingboMa

src/debugging.jl

@@ -23,13 +23,14 @@ end
 
 function logged_fun(f, args...)
     # Currently we don't really support complex numbers
-    term(LoggedFun(f, args), args..., type=Real)
+    term(LoggedFun(f, args), args..., type = Real)
 end
 
 debug_sub(eq::Equation) = debug_sub(eq.lhs) ~ debug_sub(eq.rhs)
 function debug_sub(ex)
     istree(ex) || return ex
     f = operation(ex)
     args = map(debug_sub, arguments(ex))
-    f in LOGGED_FUN ? logged_fun(f, args...) : similarterm(ex, f, args, metadata=metadata(ex))
+    f in LOGGED_FUN ? logged_fun(f, args...) :
+    similarterm(ex, f, args, metadata = metadata(ex))
 end

test/odesystem.jl

@@ -889,3 +889,15 @@ eqs = [D(q) ~ -p / L - F
 testdict = Dict([:name => "test"])
 @named sys = ODESystem(eqs, t, metadata = testdict)
 @test get_metadata(sys) == testdict
+
+@variables t P(t)=0 Q(t)=2
+∂t = Differential(t)
+
+eqs = [∂t(Q) ~ 1 / sin(P)
+       ∂t(P) ~ log(-cos(Q))]
+@named sys = ODESystem(eqs, t, [P, Q], [])
+sys = debug_system(sys);
+prob = ODEProblem(sys, [], (0, 1.0));
+du = zero(prob.u0);
+@test_throws "-cos(Q(t))" prob.f(du, [1, 0], prob.p, 0.0)
+@test_throws "sin(P(t))" prob.f(du, [0, 2], prob.p, 0.0)