test: fix symbolic events test

Author: AayushSabharwal

test/symbolic_events.jl

@@ -829,8 +829,8 @@ let
     sol = solve(prob, Tsit5(), saveat = 0.1)
 
     @test typeof(oneosc_ce_simpl) == ODESystem
-    @test sol[1, 6] < 1.0 # test whether x(t) decreases over time
-    @test sol[1, 18] > 0.5 # test whether event happened
+    @test sol[oscce.x, 6] < 1.0 # test whether x(t) decreases over time
+    @test sol[oscce.x, 18] > 0.5 # test whether event happened
 end
 
 @testset "Additional SymbolicContinuousCallback options" begin