First cut of pulling out the relevant parts of my original game to make a little framework.

tests/battle.cpp

@@ -0,0 +1,92 @@
+#include <catch2/catch_test_macros.hpp>
+#include <iostream>
+#include <set>
+#include "combat/battle.hpp"
+#include "algos/simplefsm.hpp"
+#include "algos/dinkyecs.hpp"
+#include "gui/backend.hpp"
+#include "game/level.hpp"
+#include "game/components.hpp"
+#include "ai/ai.hpp"
+#include "graphics/palette.hpp"
+
+using namespace combat;
+using namespace components;
+
+TEST_CASE("battle operations fantasy", "[combat-battle]") {
+  ai::reset();
+  ai::init("ai");
+
+  auto ai_start = ai::load_state("Enemy::initial_state");
+  auto ai_goal = ai::load_state("Enemy::final_state");
+  auto host_start = ai::load_state("Host::initial_state");
+  auto host_goal = ai::load_state("Host::final_state");
+  BattleEngine battle;
+
+  DinkyECS::Entity host = 0;
+  ai::EntityAI host_ai("Host::actions", host_start, host_goal);
+  components::Combat host_combat{
+    .hp=100, .max_hp=100, .ap_delta=6, .max_ap=12, .damage=20};
+  battle.add_enemy({host, &host_ai, &host_combat, true});
+
+  DinkyECS::Entity axe_ranger = 1;
+  ai::EntityAI axe_ai("Enemy::actions", ai_start, ai_goal);
+  components::Combat axe_combat{
+    .hp=20, .max_hp=20, .ap_delta=8, .max_ap=12, .damage=20};
+  battle.add_enemy({axe_ranger, &axe_ai, &axe_combat});
+
+  DinkyECS::Entity rat = 2;
+  ai::EntityAI rat_ai("Enemy::actions", ai_start, ai_goal);
+  components::Combat rat_combat{
+    .hp=10, .max_hp=10, .ap_delta=2, .max_ap=10, .damage=10};
+  battle.add_enemy({rat, &rat_ai, &rat_combat});
+
+  battle.set_all("enemy_found", true);
+  battle.set_all("in_combat", true);
+  battle.set_all("tough_personality", true);
+  battle.set_all("health_good", true);
+
+  battle.set(rat, "tough_personality", false);
+  battle.set(host, "have_healing", false);
+  battle.set(host, "tough_personality", false);
+
+  while(host_combat.hp > 0) {
+    battle.set(host, "health_good", host_combat.hp > 20);
+
+    battle.player_request("use_healing");
+    battle.player_request("kill_enemy");
+
+    battle.ap_refresh();
+    battle.plan();
+
+    while(auto act = battle.next()) {
+      auto& [enemy, wants_to, cost, enemy_state] = *act;
+
+      // fmt::println(">>>>> entity: {} wants to {} cost={}; has {} HP; {} ap",
+      //     enemy.entity, wants_to,
+      //     cost, enemy.combat->hp,
+      //     enemy.combat->ap);
+
+      switch(enemy_state) {
+        case BattleHostState::agree:
+          // fmt::println("HOST and PLAYER requests match {}, doing it.", wants_to);
+          break;
+        case BattleHostState::disagree:
+          // fmt::println("REBELIOUS ACT: {}", wants_to);
+          battle.clear_requests();
+          REQUIRE(battle.$player_requests.size() == 0);
+          break;
+        case BattleHostState::not_host:
+         if(wants_to == "kill_enemy") {
+          enemy.combat->attack(host_combat);
+         }
+         break;
+        case BattleHostState::out_of_ap:
+         // fmt::println("ENEMY OUT OF AP");
+         break;
+      }
+    }
+
+    REQUIRE(!battle.next());
+  }
+}