test: update tests to account for changes to array hack

Author: AayushSabharwal

test/initializationsystem.jl

@@ -1347,8 +1347,8 @@ end
         guesses = [p[1] => q, p[2] => 2q])
     @test ModelingToolkit.is_parameter_solvable(p, Dict(), defaults(sys), guesses(sys))
     prob = ODEProblem(sys, [x => 1.0], (0.0, 1.0), [q => 2.0])
-    @test length(ModelingToolkit.observed(prob.f.initialization_data.initializeprob.f.sys)) ==
-          3
+    initsys = prob.f.initialization_data.initializeprob.f.sys
+    @test length(ModelingToolkit.observed(initsys)) == 4
     sol = solve(prob, Tsit5())
     @test sol.ps[p] ≈ [2.0, 4.0]
 end

test/reduction.jl

@@ -176,7 +176,7 @@ A = reshape(1:(N^2), N, N)
 eqs = xs ~ A * xs
 @named sys′ = NonlinearSystem(eqs, [xs], [])
 sys = structural_simplify(sys′)
-@test length(equations(sys)) == 3 && length(observed(sys)) == 2
+@test length(equations(sys)) == 3 && length(observed(sys)) == 3
 
 # issue 958
 @parameters k₁ k₂ k₋₁ E₀

test/structural_transformation/utils.jl

@@ -76,7 +76,7 @@ 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)) == 4
     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)