add tests with integrator callbacks

Author: Datseris

test/REQUIRE

@@ -0,0 +1 @@
+DiffEqCallbacks 2.1

test/integrators_with_callbacks.jl

@@ -1,4 +1,56 @@
 using DiffEqCallbacks
+using DynamicalSystemsBase
+using OrdinaryDiffEq: Vern7, Tsit5
+using LinearAlgebra
+
+@testset "SavingCallback parallel" begin
+
+kwargs = (abstol=1e-14, reltol=1e-14, solver=Vern7(), maxiters=1e9)
+ds = Systems.lorenz()
+d0 = 1e-9
+T = 100.0
+
+save_func(u, t, integrator) = LinearAlgebra.norm(u[1] - u[2])
+saved_values = SavedValues(eltype(ds.t0), eltype(ds.u0[1]))
+cb = SavingCallback(save_func, saved_values)
+
+u0 = get_state(ds)
+pinteg = parallel_integrator(ds, [u0, u0 + rand(SVector{3})*d0];
+kwargs..., callback = cb)
+step!(pinteg, T)
+n = saved_values.saveval
+t = saved_values.t
+@test length(n) > 1000
+# test that norm increases:
+@test n[2] > n[1]
+@test n[end] > n[5]
+@test length(pinteg.sol.u) == 1
+end
+
+
+@testset "SavingCallback tangent" begin
+
+kwargs = (abstol=1e-14, reltol=1e-14, solver=Tsit5())
+ds = Systems.lorenz()
+d0 = 1e-9
+T = 100.0
+
+save_func(u, t, integrator) = LinearAlgebra.norm(get_deviations(integrator)[1, :])
+saved_values = SavedValues(eltype(ds.t0), eltype(ds.u0[1]))
+cb = SavingCallback(save_func, saved_values)
+
+u0 = get_state(ds)
+pinteg = tangent_integrator(ds; kwargs..., callback = cb)
+step!(pinteg, T)
+n = saved_values.saveval
+t = saved_values.t
+@test length(n) > 1000
+# test that norm increases:
+@test mean(n[10000:11000]) > mean(n[1:100])
+@test n[end] > n[5]
+@test length(pinteg.sol.u) == 1
+
+end
 
 #=
 @testset "ManifoldProjection" begin

test/math_tests.jl

@@ -1,6 +1,4 @@
-if current_module() != DynamicalSystemsBase
-  using DynamicalSystemsBase
-end
+using DynamicalSystemsBase
 using Test, StaticArrays
 println("Testing custom QR-decomposition...")