try to fix test

Author: isaacsas

test/ssa_callback_test.jl

@@ -25,13 +25,13 @@ function fuel_affect!(integrator)
 end
 cb = DiscreteCallback(condition, fuel_affect!, save_positions = (false, true))
 
-sol = solve(jump_prob, SSAStepper(), callback = cb, tstops = [5])
+sol = solve(jump_prob, SSAStepper(); callback = cb, tstops = [5])
 @test sol.t[1:2] == [0.0, 5.0] # no jumps between t=0 and t=5
 @test sol(5 + 1e-10) == [100, 0] # state just after fueling before any decays can happen
 
 # test can pass callbacks via JumpProblem
 jump_prob2 = JumpProblem(prob, Direct(), jump; rng = rng, callback = cb)
-sol2 = solve(jump_prob2, SSAStepper(), tstops = [5])
+sol2 = solve(jump_prob2, SSAStepper(); tstops = [5])
 @test sol2.t[1:2] == [0.0, 5.0] # no jumps between t=0 and t=5
 @test sol2(5 + 1e-10) == [100, 0] # state just after fueling before any decays can happen