Add test

test/variable_rate.jl

@@ -191,3 +191,25 @@ let
     @test_throws ErrorException JumpProblem(dprob_, alg, mass_action_jump_, vrj;
                                             save_positions = (false, false))
 end
+
+# https://github.com/SciML/JumpProcesses.jl/issues/330
+let
+    test_rate(u, p, t) = 3.0 
+    test_affect!(integrator) = (integrator.u[1] += 1)
+    function test_urate(u, p, t) 
+        if t > 1.0
+            error("test_urate does not handle t > 1.0")
+        else
+            return 4.0
+        end
+    end
+
+    test_jump = VariableRateJump(test_rate, test_affect!; urate=test_urate, rateinterval=(u,p,t)->0.9)
+
+    dprob = DiscreteProblem([0], (0.0, 1.0), nothing) 
+    jprob = JumpProblem(dprob, Coevolve(), test_jump; dep_graph=[[1]])
+
+    @test_nowarn for i in 1:100
+        solve(jprob, SSAStepper())
+    end
+end