From d7fb363e2ab0b6eaf2417bc677a396116d55187a Mon Sep 17 00:00:00 2001
From: Sam Isaacson <isaacsas@users.noreply.github.com>
Date: Tue, 13 Aug 2024 13:47:49 -0400
Subject: [PATCH] add tests and format

---
 README.md                 |  1 -
 src/SSA_stepper.jl        |  5 ++---
 test/ssa_callback_test.jl | 33 +++++++++++++++++++++++++++------
 3 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/README.md b/README.md
index c1b1f1a6..badc20c7 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,6 @@
 
 <!-- [![Coverage Status](https://coveralls.io/repos/github/SciML/JumpProcesses.jl/badge.svg?branch=master)](https://coveralls.io/github/SciML/JumpProcesses.jl?branch=master)
 [![codecov](https://codecov.io/gh/SciML/JumpProcesses.jl/branch/master/graph/badge.svg)](https://codecov.io/gh/SciML/JumpProcesses.jl) -->
-
 [![Build Status](https://github.com/SciML/JumpProcesses.jl/workflows/CI/badge.svg)](https://github.com/SciML/JumpProcesses.jl/actions?query=workflow%3ACI)
 [![ColPrac: Contributor's Guide on Collaborative Practices for Community Packages](https://img.shields.io/badge/ColPrac-Contributor%27s%20Guide-blueviolet)](https://github.com/SciML/ColPrac)
 [![SciML Code Style](https://img.shields.io/static/v1?label=code%20style&message=SciML&color=9558b2&labelColor=389826)](https://github.com/SciML/SciMLStyle)
diff --git a/src/SSA_stepper.jl b/src/SSA_stepper.jl
index 9cd9e968..70039ee6 100644
--- a/src/SSA_stepper.jl
+++ b/src/SSA_stepper.jl
@@ -163,7 +163,6 @@ function DiffEqBase.__init(jump_prob::JumpProblem,
         tstops = nothing,
         alias_tstops = false,
         numsteps_hint = 100)
-
     if !(jump_prob.prob isa DiscreteProblem)
         error("SSAStepper only supports DiscreteProblems.")
     end
@@ -264,10 +263,10 @@ function DiffEqBase.add_tstop!(integrator::SSAIntegrator, tstop)
             tstops = integrator.tstops
         else
             integrator.copied_tstops = true
-            tstops = copy(integrator.tstops)
+            integrator.tstops = copy(integrator.tstops)
         end
 
-        Base.insert!(tstops, insert_index, tstop)
+        Base.insert!(integrator.tstops, insert_index, tstop)
     end
     nothing
 end
diff --git a/test/ssa_callback_test.jl b/test/ssa_callback_test.jl
index 0e5a0992..acbbd073 100644
--- a/test/ssa_callback_test.jl
+++ b/test/ssa_callback_test.jl
@@ -134,9 +134,9 @@ cb = PresetTimeCallback(cbtimes, affectpresets!)
 jsol = solve(jprob, SSAStepper(), saveat = 0.1, callback = cb)
 @test (jsol(20.00000000001) - jsol(19.9999999999))[1] == 10
 
-# tests for periodic callbacks working, i.e. #417
+# test periodic callbacks working, i.e. #417
 let
-    rate(u,p,t) = 0.0
+    rate(u, p, t) = 0.0
     affect!(integ) = (nothing)
     crj = ConstantRateJump(rate, affect!)
     dprob = DiscreteProblem([0], (0.0, 10.0))
@@ -144,16 +144,37 @@ let
     cb = PeriodicCallback(cbfun, 1.0)
     jprob = JumpProblem(dprob, crj; rng)
     sol = solve(jprob; callback = cb)
-    @test sol[1,end] == 9
+    @test sol[1, end] == 9
 
     cb = PeriodicCallback(cbfun, 1.0; initial_affect = true)
     jprob = JumpProblem(dprob, crj; rng)
     sol = solve(jprob; callback = cb)
-    @test sol[1,end] == 10
+    @test sol[1, end] == 10
 
     cb = PeriodicCallback(cbfun, 1.0; initial_affect = true, final_affect = true)
     jprob = JumpProblem(dprob, crj; rng)
     sol = solve(jprob; callback = cb)
-    @test sol[1,end] == 11
+    @test sol[1, end] == 11
+end
 
-end
\ No newline at end of file
+# test for tstops aliasing, i.e.#442
+let
+    rate(u, p, t) = 0.0
+    affect!(integ) = (nothing)
+    crj = ConstantRateJump(rate, affect!)
+    dprob = DiscreteProblem([0], (0.0, 10.0))
+    cbfun(integ) = (integ.u[1] += 1; nothing)
+    cb = PeriodicCallback(cbfun, 1.0)
+    jprob = JumpProblem(dprob, crj; rng)
+    tstops = Float64[]
+    sol = solve(jprob; callback = cb, tstops, alias_tstops = true)
+    @test sol[1, end] == 9
+    @test tstops == 1.0:9.0
+    empty!(tstops)
+    sol = solve(jprob; callback = cb, tstops, alias_tstops = false)
+    @test sol[1, end] == 9
+    @test isempty(tstops)
+    sol = solve(jprob; callback = cb, tstops)
+    @test sol[1, end] == 9
+    @test isempty(tstops)
+end