test: update tests to account for removal of CSE hack

Author: AayushSabharwal

test/structural_transformation/utils.jl

@@ -50,7 +50,7 @@ end
     @mtkbuild sys = ODESystem(
         [D(x) ~ z[1] + z[2] + foo(z)[1], y[1] ~ 2t, y[2] ~ 3t, z ~ foo(y)], t)
     @test length(equations(sys)) == 1
-    @test length(observed(sys)) == 7
+    @test length(observed(sys)) == 6
     @test any(eq -> isequal(eq.lhs, y), observed(sys))
     @test any(eq -> isequal(eq.lhs, z), observed(sys))
     prob = ODEProblem(sys, [x => 1.0], (0.0, 1.0), [foo => _tmp_fn])
@@ -75,7 +75,7 @@ end
     end
     @mtkbuild sys = ODESystem([D(x) ~ y[1] + y[2], y ~ foo(x)], t)
     @test length(equations(sys)) == 1
-    @test length(observed(sys)) == 3
+    @test length(observed(sys)) == 2
     prob = ODEProblem(sys, [x => 1.0], (0.0, 1.0), [foo => _tmp_fn2])
     val[] = 0
     @test_nowarn prob.f(prob.u0, prob.p, 0.0)
@@ -88,32 +88,9 @@ end
         iscall(eq.rhs) && operation(eq.rhs) in [StructuralTransformations.getindex_wrapper,
             StructuralTransformations.change_origin]
     end
-
-    @testset "CSE hack in equations(sys)" begin
-        val[] = 0
-        @variables z(t)[1:2]
-        @mtkbuild sys = ODESystem(
-            [D(y) ~ foo(x), D(x) ~ sum(y), zeros(2) ~ foo(prod(z))], t)
-        @test length(equations(sys)) == 5
-        @test length(observed(sys)) == 2
-        prob = ODEProblem(
-            sys, [y => ones(2), z => 2ones(2), x => 3.0], (0.0, 1.0), [foo => _tmp_fn2])
-        val[] = 0
-        @test_nowarn prob.f(prob.u0, prob.p, 0.0)
-        @test val[] == 2
-
-        isys = ModelingToolkit.generate_initializesystem(sys)
-        @test length(unknowns(isys)) == 5
-        @test length(equations(isys)) == 2
-        @test !any(equations(isys)) do eq
-            iscall(eq.rhs) &&
-                operation(eq.rhs) in [StructuralTransformations.getindex_wrapper,
-                    StructuralTransformations.change_origin]
-        end
-    end
 end
 
-@testset "array and cse hacks can be disabled" begin
+@testset "array hacks can be disabled" begin
     @testset "fully_determined = true" begin
         @variables x(t) y(t)[1:2] z(t)[1:2]
         @parameters foo(::AbstractVector)[1:2]
@@ -129,7 +106,7 @@ end
         end
 
         sys2 = structural_simplify(sys; array_hack = false)
-        @test length(observed(sys2)) == 5
+        @test length(observed(sys2)) == 4
         @test !any(observed(sys2)) do eq
             iscall(eq.rhs) && operation(eq.rhs) == StructuralTransformations.change_origin
         end
@@ -150,7 +127,7 @@ end
         end
 
         sys2 = structural_simplify(sys; array_hack = false, fully_determined = false)
-        @test length(observed(sys2)) == 5
+        @test length(observed(sys2)) == 4
         @test !any(observed(sys2)) do eq
             iscall(eq.rhs) && operation(eq.rhs) == StructuralTransformations.change_origin
         end