test: remove unneeded initial conditions

with newer versions of MTK we no longer need to provides these,
as initialization can find the appropriate initial conditions.
If the extra u0s are provided, they lead to initialization failures.

test/Blocks/sources.jl

@@ -25,7 +25,7 @@ end
 
 @testset "TimeVaryingFunction" begin
     f(t) = t^2 + 1
-    vars = @variables y(t)=1 dy(t)=0 ddy(t)=0
+    vars = @variables y(t) dy(t) ddy(t)
     @named src = TimeVaryingFunction(f)
     @named int = Integrator()
     @named iosys = ODESystem(

test/Thermal/demo.jl

@@ -20,7 +20,7 @@ using OrdinaryDiffEq: ReturnCode.Success
     @named model = ODESystem(connections, t,
         systems = [mass1, mass2, conduction, Tsensor1, Tsensor2])
     sys = structural_simplify(model)
-    prob = ODEProblem(sys, [mass1.der_T => 1.0, mass2.der_T => 1.0], (0, 3.0))
+    prob = ODEProblem(sys, [], (0, 3.0))
     sol = solve(prob, Tsit5())
     @test SciMLBase.successful_retcode(sol)
 end

test/Thermal/piston.jl

@@ -33,9 +33,7 @@ using ModelingToolkitStandardLibrary.Blocks
 
     @mtkbuild piston = Piston()
 
-    u0 = [piston.coolant.dT => 5.0
-          piston.wall.Q_flow => 10.0]
-    prob = ODEProblem(piston, u0, (0, 3.0))
+    prob = ODEProblem(piston, [], (0, 3.0))
     sol = solve(prob)
 
     # Heat-flow-rate is equal in magnitude

test/Thermal/thermal.jl

@@ -22,8 +22,7 @@ using OrdinaryDiffEq: ReturnCode.Success
     @named h1 = ODESystem(eqs, t, systems = [mass1, reltem_sensor, tem_src, th_conductor])
     sys = structural_simplify(h1)
 
-    u0 = [mass1.T => 2.0
-          mass1.der_T => 1.0]
+    u0 = [mass1.T => 2]
     prob = ODEProblem(sys, u0, (0, 2.0))
     sol = solve(prob, Tsit5())
 
@@ -42,10 +41,7 @@ using OrdinaryDiffEq: ReturnCode.Success
     sys = structural_simplify(h2)
 
     u0 = [mass1.T => 1.0
-          mass2.T => 10.0
-          final_T => 12
-          mass1.der_T => 1.0
-          mass2.der_T => 1.0]
+          mass2.T => 10.0]
     prob = ODEProblem(sys, u0, (0, 3.0))
     sol = solve(prob, Tsit5())
 
@@ -79,9 +75,7 @@ end
             th_resistor, flow_src, th_ground, th_conductor])
     sys = structural_simplify(h2)
 
-    u0 = [mass1.T => 10.0
-          th_resistor.Q_flow => 1.0
-          mass1.der_T => 1.0]
+    u0 = [mass1.T => 10.0]
     prob = ODEProblem(sys, u0, (0, 3.0))
     sol = solve(prob, Tsit5())
 
@@ -121,9 +115,7 @@ end
         ])
     sys = structural_simplify(rad)
 
-    u0 = [base.Q_flow => 10
-          dissipator.Q_flow => 10
-          mass.T => T_gas]
+    u0 = [mass.T => T_gas]
     prob = ODEProblem(sys, u0, (0, 3.0))
     sol = solve(prob, Rodas4())
 
@@ -152,7 +144,6 @@ end
     sys = structural_simplify(coll)
 
     u0 = [
-        th_resistor.Q_flow => 1.0,
         mass.T => 0.0
     ]
     prob = ODEProblem(sys, u0, (0, 3.0))