fix testsZ

src/world/OverworldController.lua

@@ -3517,10 +3517,21 @@ end
 
 function OverworldState:onStepComplete()
   local p = self.player
-  local suppressWildEncounter = self.wildEncounterGraceSteps > 0
-  if suppressWildEncounter then
-    self.wildEncounterGraceSteps = self.wildEncounterGraceSteps - 1
+  -- Defaulted: a state built without the constructor (a mod harness, a test
+  -- fixture) reaches this before :234 ever ran, and nil > 0 threw the step.
+  local grace = self.wildEncounterGraceSteps or 0
+  if grace > 0 then
+    self.wildEncounterGraceSteps = grace - 1
   end
+  -- TryDoWildEncounter's first guard is `ld a, [wNPCMovementScriptPointerTable
+  -- Num] / and a / ret nz` (engine/battle/wild_encounters.asm:3-9): a step the
+  -- player did not take never rolls, which is why Oak's escort walks to the lab
+  -- through Pallet's grass without being jumped.
+  local runner = self.runner
+  local scripted = (runner and runner.isRunning and runner:isRunning())
+    or #(self.scriptMoves or {}) > 0
+    or self.engaging or self.emote or self.teleportOut
+  local suppressWildEncounter = grace > 0 or scripted and true or false
   self.todSteps = (self.todSteps or 0) + 1
   -- UpdatePikachuHappinessAndMood rides the step counter (poison.asm)
   require("src.world.PikachuFollower").onStep(Game.save)