fixup! test: test parameters as initialization unknowns

Author: AayushSabharwal

test/initializationsystem.jl

@@ -490,19 +490,21 @@ end
 @testset "Initialization of parameters" begin
     function test_parameter(prob, sym, val, initialval = zero(val))
         @test prob.ps[sym] ≈ initialval
-        @test init(prob).ps[sym] ≈ val
-        @test solve(prob).ps[sym] ≈ val
+        @test init(prob, Tsit5()).ps[sym] ≈ val
+        @test solve(prob, Tsit5()).ps[sym] ≈ val
     end
     @variables x(t) y(t)
     @parameters p
     _p = ModelingToolkit.setdefault(p, missing)
+    _p = ModelingToolkit.setguess(_p, 0.0)
     @mtkbuild sys = ODESystem([D(x) ~ x, _p ~ x + y], t)
     prob = ODEProblem(sys, [x => 1.0, y => 1.0], (0.0, 1.0))
     test_parameter(prob, _p, 2.0)
-    @mtkbuild sys = ODESystem([D(x) ~ x, p ~ x + y], t; defaults = [p => missing])
+    @mtkbuild sys = ODESystem(
+        [D(x) ~ x, p ~ x + y], t; defaults = [p => missing], guesses = [p => 0.0])
     prob = ODEProblem(sys, [x => 1.0, y => 1.0], (0.0, 1.0))
     test_parameter(prob, p, 2.0)
-    @mtkbuild sys = ODESystem([D(x) ~ x, p ~ x + y], t)
+    @mtkbuild sys = ODESystem([D(x) ~ x, p ~ x + y], t; guesses = [p => 0.0])
     prob = ODEProblem(sys, [x => 1.0, y => 1.0], (0.0, 1.0), [p => missing])
     test_parameter(prob, p, 2.0)
 
@@ -516,7 +518,7 @@ end
     @testset "Null system" begin
         @variables x(t) y(t) s(t)
         @parameters x0 y0
-        @mtkbuild sys = ODESystem([x ~ x0, y ~ y0, s ~ x + y], t)
+        @mtkbuild sys = ODESystem([x ~ x0, y ~ y0, s ~ x + y], t; guesses = [y0 => 0.0])
         prob = ODEProblem(sys, [s => 1.0], (0.0, 1.0), [x0 => 0.3, y0 => missing])
         test_parameter(prob, y0, 0.7)
     end