Fix test

Author: HarrisonGrodin

src/equations.jl

@@ -6,6 +6,7 @@ mutable struct Equation
     rhs::Expression
 end
 Base.broadcastable(eq::Equation) = Ref(eq)
+Base.:(==)(a::Equation, b::Equation) = (a.lhs, a.rhs) == (b.lhs, b.rhs)
 
 Base.:~(lhs::Expression, rhs::Expression) = Equation(lhs, rhs)
 Base.:~(lhs::Expression, rhs::Number    ) = Equation(lhs, rhs)

src/systems/diffeqs/diffeqsystem.jl

@@ -12,6 +12,7 @@ function Base.convert(::Type{DiffEq}, eq::Equation)
     isintermediate(eq) && throw(ArgumentError("intermediate equation received"))
     return DiffEq(eq.lhs.op, eq.lhs.args[1], eq.rhs)
 end
+Base.:(==)(a::DiffEq, b::DiffEq) = (a.D, a.var, a.rhs) == (b.D, b.var, b.rhs)
 get_args(eq::DiffEq) = Expression[eq.var, eq.rhs]
 
 struct DiffEqSystem <: AbstractSystem

src/systems/diffeqs/first_order_transform.jl

@@ -30,25 +30,26 @@ function ode_order_lowering!(eqs, naming_scheme)
             var_order[var] = maxorder
             var ∈ vars || push!(vars, var)
         end
-        lhs_renaming!(eq, naming_scheme)
+        lhs_renaming!(eq, D, naming_scheme)
         rhs_renaming!(eq, naming_scheme)
     end
 
     for var ∈ vars
         order = var_order[var]
         for o in (order-1):-1:1
-            lhs = D(lower_varname(var, idv, o-1, naming_scheme))
+            lvar = lower_varname(var, idv, o-1, naming_scheme)
             rhs = lower_varname(var, idv, o, naming_scheme)
-            eq = Equation(lhs, rhs)
+            eq = DiffEq(D, lvar, rhs)
             push!(eqs, eq)
         end
     end
 
     return eqs
 end
 
-function lhs_renaming!(eq::DiffEq, naming_scheme)
+function lhs_renaming!(eq::DiffEq, D, naming_scheme)
     eq.var = lower_varname(eq.D, eq.var, naming_scheme, lower=true)
+    eq.D = D
     return eq
 end
 rhs_renaming!(eq::DiffEq, naming_scheme) = _rec_renaming!(eq.rhs, naming_scheme)

test/system_construction.jl

@@ -45,7 +45,7 @@ lowered_eqs = [D(u_tt) ~ 2u_tt + u_t + x_t + 1
                D(u_t)  ~ u_tt
                D(u)    ~ u_t
                D(x)    ~ x_t]
-@test_broken de1.eqs == lowered_eqs
+@test de1.eqs == convert.(ModelingToolkit.DiffEq, lowered_eqs)
 
 # Internal calculations
 a = y - x