Add working tests

Author: bolognam

src/structural_transformation/StructuralTransformations.jl

@@ -12,11 +12,13 @@ using SymbolicUtils.Rewriters
 using SymbolicUtils: similarterm, istree
 
 using ModelingToolkit
-using ModelingToolkit: ODESystem, var_from_nested_derivative, Differential,
-                       states, equations, vars, Symbolic, diff2term, value,
-                       operation, arguments, Sym, Term, simplify, solve_for,
-                       isdiffeq, isdifferential,
-                       get_structure, defaults, InvalidSystemException
+using ModelingToolkit: ODESystem, AbstractSystem, var_from_nested_derivative,
+                       Differential, states, equations, vars, Symbolic,
+                       diff2term, value, operation, arguments, Sym, Term,
+                       simplify, solve_for, isdiffeq, isdifferential,
+                       get_structure, defaults, InvalidSystemException,
+                       ExtraEquationsSystemException,
+                       ExtraVariablesSystemException
 
 using ModelingToolkit.BipartiteGraphs
 using ModelingToolkit.SystemStructures

src/structural_transformation/utils.jl

@@ -57,14 +57,26 @@ function error_reporting(sys, bad_idxs, n_highest_vars, iseqs)
         out_arr = structure(sys).fullvars[bad_idxs]
     end
 
-    msg = String(take!(Base.print_array(io, out_arr)))
+    Base.print_array(io, out_arr)
+    msg = String(take!(io))
     neqs = length(equations(sys))
-    throw(InvalidSystemException(
-        "The system is unbalanced. "
-        * "There are $n_highest_vars highest order derivative variables "
-        * "and $neqs equations.\n"
-        * msg
-    ))
+    if iseqs
+        throw(ExtraEquationsSystemException(
+            "The system is unbalanced. "
+            * "There are $n_highest_vars highest order derivative variables "
+            * "and $neqs equations.\n"
+            * error_title
+            * msg
+        ))
+    else
+        throw(ExtraVariablesSystemException(
+            "The system is unbalanced. "
+            * "There are $n_highest_vars highest order derivative variables "
+            * "and $neqs equations.\n"
+            * error_title
+            * msg
+        ))
+    end
 end
 
 ###
@@ -81,7 +93,7 @@ function check_consistency(sys::AbstractSystem)
         varwhitelist = varassoc .== 0
         assign = matching(graph, varwhitelist) # not assigned
         # Just use `error_reporting` to do conditional
-        iseqs = n_highest_vars > neqs
+        iseqs = n_highest_vars < neqs
 
         if iseqs
             bad_idxs = findall(isequal(UNASSIGNED), assign)

src/systems/abstractsystem.jl

@@ -665,6 +665,16 @@ struct InvalidSystemException <: Exception
 end
 Base.showerror(io::IO, e::InvalidSystemException) = print(io, "InvalidSystemException: ", e.msg)
 
+struct ExtraVariablesSystemException <: Exception
+    msg::String
+end
+Base.showerror(io::IO, e::ExtraVariablesSystemException) = print(io, "ExtraVariablesSystemException: ", e.msg)
+
+struct ExtraEquationsSystemException <: Exception
+    msg::String
+end
+Base.showerror(io::IO, e::ExtraEquationsSystemException) = print(io, "ExtraEquationsSystemException: ", e.msg)
+
 AbstractTrees.children(sys::ModelingToolkit.AbstractSystem) = ModelingToolkit.get_systems(sys)
 AbstractTrees.printnode(io::IO, sys::ModelingToolkit.AbstractSystem) = print(io, nameof(sys))
 AbstractTrees.nodetype(::ModelingToolkit.AbstractSystem) = ModelingToolkit.AbstractSystem

test/error_handling.jl

@@ -0,0 +1,105 @@
+using Test
+using ModelingToolkit#, OrdinaryDiffEq
+import ModelingToolkit: ExtraVariablesSystemException, ExtraEquationsSystemException
+
+@parameters t
+function Pin(;name)
+    @variables v(t) i(t)
+    ODESystem(Equation[], t, [v, i], [], name=name, defaults=[v=>1.0, i=>1.0])
+end
+
+function UnderdefinedConstantVoltage(;name, V = 1.0)
+    val = V
+    @named p = Pin()
+    @named n = Pin()
+    @parameters V
+    eqs = [
+           V ~ p.v - n.v
+           #0 ~ p.i + n.i
+          ]
+    ODESystem(eqs, t, [], [V], systems=[p, n], defaults=Dict(V => val), name=name)
+end
+
+function OverdefinedConstantVoltage(;name, V = 1.0, I = 1.0)
+    val = V
+    val2 = I
+    @named p = Pin()
+    @named n = Pin()
+    @parameters V I
+    eqs = [
+           V ~ p.v - n.v
+           n.i ~ I
+           p.i ~ I
+          ]
+    ODESystem(eqs, t, [], [V], systems=[p, n], defaults=Dict(V => val, I => val2), name=name)
+end
+
+function Resistor(;name, R = 1.0)
+    val = R
+    @named p = Pin()
+    @named n = Pin()
+    @variables v(t)
+    @parameters R
+    eqs = [
+           v ~ p.v - n.v
+           0 ~ p.i + n.i
+           v ~ p.i * R
+          ]
+    ODESystem(eqs, t, [v], [R], systems=[p, n], defaults=Dict(R => val), name=name)
+end
+
+function Capacitor(;name, C = 1.0)
+    val = C
+    @named p = Pin()
+    @named n = Pin()
+    @variables v(t)
+    @parameters C
+    D = Differential(t)
+    eqs = [
+           v ~ p.v - n.v
+           0 ~ p.i + n.i
+           D(v) ~ p.i / C
+          ]
+    ODESystem(eqs, t, [v], [C], systems=[p, n], defaults=Dict(C => val), name=name)
+end
+
+function ModelingToolkit.connect(ps...)
+    eqs = [
+           0 ~ sum(p->p.i, ps) # KCL
+          ]
+    # KVL
+    for i in 1:length(ps)-1
+        push!(eqs, ps[i].v ~ ps[i+1].v)
+    end
+
+    return eqs
+end
+
+R = 1.0
+C = 1.0
+V = 1.0
+@named resistor = Resistor(R=R)
+@named capacitor = Capacitor(C=C)
+@named source = UnderdefinedConstantVoltage(V=V)
+
+rc_eqs = [
+          connect(source.p, resistor.p)
+          connect(resistor.n, capacitor.p)
+          connect(capacitor.n, source.n)
+         ]
+
+@named rc_model = ODESystem(rc_eqs, t, systems=[resistor, capacitor, source])
+
+
+@test_throws ModelingToolkit.ExtraVariablesSystemException structural_simplify(rc_model)
+
+
+@named source2 = OverdefinedConstantVoltage(V=V, I=V/R)
+rc_eqs2 = [
+          connect(source2.p, resistor.p)
+          connect(resistor.n, capacitor.p)
+          connect(capacitor.n, source2.n)
+         ]
+
+@named rc_model2 = ODESystem(rc_eqs2, t, systems=[resistor, capacitor, source2])
+@test_throws ModelingToolkit.ExtraEquationsSystemException structural_simplify(rc_model2)

test/runtests.jl

@@ -38,3 +38,4 @@ println("Last test requires gcc available in the path!")
 @testset "Serialization" begin include("serialization.jl") end
 @safetestset "print_tree" begin include("print_tree.jl") end
 @safetestset "connectors" begin include("connectors.jl") end
+@safetestset "error_handling" begin include("error_handling.jl") end