Ensure stability of rand between Julia versions (#196)

Author: henry2004y

test/Project.toml

@@ -3,5 +3,6 @@ CairoMakie = "13f3f980-e62b-5c42-98c6-ff1f3baf88f0"
 Meshes = "eacbb407-ea5a-433e-ab97-5258b1ca43fa"
 OrdinaryDiffEq = "1dea7af3-3e70-54e6-95c3-0bf5283fa5ed"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
+StableRNGs = "860ef19b-820b-49d6-a774-d7a799459cd3"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"

test/runtests.jl

@@ -1,11 +1,12 @@
-using TestParticle, OrdinaryDiffEq, StaticArrays, Random
+using TestParticle, OrdinaryDiffEq, StaticArrays
 using TestParticle: Field, qᵢ, mᵢ, qₑ, mₑ, c, guiding_center
 using Meshes: CartesianGrid
+using Random, StableRNGs
 using Test
 
 "Initial state perturbation for EnsembleProblem."
 function prob_func(prob, i, repeat)
-   remake(prob, u0=rand(MersenneTwister(i))*prob.u0)
+   remake(prob, u0=rand(StableRNG(i))*prob.u0)
 end
 
 function prob_func_boris_mutable(prob, i, repeat)
@@ -127,7 +128,7 @@ end
 
       x = getindex.(sol.u[10].u, 1)
 
-      @test x[7] ≈ 0.09615629718624641 rtol=1e-6
+      @test x[7] ≈ 0.08230289216655486 rtol=1e-6
 
       stateinit = SA[x0..., u0...]
       tspan = (0.0, 1.0)