Battle-for-Tismo/tests/simple_snapshot_test.js

// The simple economy's wire shape (10-snapshot-and-orders.md): which snapshot
// fields the client needs to render the pool and the global market, that the
// market is delta-shipped on its own version, and that `market_trade` is
// validated on the server. The hard model's snapshot must stay untouched.

import { TestCase } from "./framework/test_case.js";
import { simpleState, smallState, smallConfig, SEED } from "./framework/helpers.js";
import { GameServer } from "../server/game_server.js";
import {
  RESOURCE_IDS,
  STORABLE_RESOURCE_IDS,
  RESOURCE_MARKET_BASE,
  MARKET_START_STOCK,
} from "../shared/data.js";

function fakeNetwork() {
  return {
    peers: new Set(),
    sent: [],
    getPeerIds() {
      return Array.from(this.peers);
    },
    send(peerId, message) {
      this.sent.push({ peerId, message });
    },
  };
}

// A configured simple server with peer 1 mapped to civ 0, so a snapshot can be
// walked through the same delta path the real broadcast uses.
function configuredServer(economyModel) {
  const network = fakeNetwork();
  const server = new GameServer(network);
  server.configureGame({
    seed: SEED,
    player_civ: 0,
    civilisations: ["france", "britain"],
    mapConfig: smallConfig(),
    economyModel,
  });
  network.peers.add(1);
  server.peerCiv.set(1, 0);
  return { server, network };
}

function lastState(network) {
  return network.sent[network.sent.length - 1].message.state;
}

export class SimpleSnapshotTest extends TestCase {
  test_a_simple_snapshot_carries_the_model_the_pool_and_the_market() {
    const state = simpleState();
    const snap = state.snapshot(0);

    // The top-level model, so the client picks the simple UI.
    this.assertEqual(snap.economyModel, "simple", "the model ships at the top level");

    // The viewer's own pool is the `stock` of its resource summary; every
    // region reads the same four numbers.
    const pool = state.getResourcePool(0);
    for (const id of STORABLE_RESOURCE_IDS) {
      this.assertEqual(
        snap.viewerStats.resources.stock[id],
        pool[id],
        `${id} ships the viewer's pool`
      );
    }

    // The world market ships one entry per resource: stock plus the price the
    // client renders without recomputing it. Energy is a flow, never stocked.
    const market = snap.resourceMarket;
    this.assertSize(market, RESOURCE_IDS.length, "one market entry per resource");
    const steel = market.find((entry) => entry.id === "steel");
    this.assertEqual(steel.stock, MARKET_START_STOCK, "the world stock ships");
    this.assertApprox(steel.price, RESOURCE_MARKET_BASE.steel, 1e-9, "and its price");
    const energy = market.find((entry) => entry.id === "energy");
    this.assertEqual(energy.stock, null, "energy ships no stock");
  }

  test_the_shipped_pool_tracks_the_live_pool() {
    const state = simpleState();
    state.getResourcePool(0).steel = 4242;
    this.assertEqual(
      state.snapshot(0).viewerStats.resources.stock.steel,
      4242,
      "an edit to the pool is visible to the very next snapshot"
    );
  }

  test_a_hard_snapshot_keeps_its_own_market() {
    const state = smallState();
    state.applyStartingScenario();
    const snap = state.snapshot(0);
    this.assertEqual(snap.economyModel, "hard", "the hard model is reported");
    this.assertEqual(typeof state.getResourcePool, "undefined", "there is no pool API");
    // The hard market is still the supply/demand listing: it ships no stock and
    // keeps its own price and supply/demand fields.
    const steel = snap.resourceMarket.find((entry) => entry.id === "steel");
    this.assertEqual(steel.stock, null, "the hard market ships no stock");
    this.assertEqual(typeof steel.supply, "number", "but it keeps its supply");
    this.assertEqual(typeof steel.demand, "number", "and its demand");
    const versionBefore = snap.versions.market;
    for (let hour = 0; hour < 24; hour++) state.advanceHour();
    this.assertGreater(
      state.snapshot(0).versions.market,
      versionBefore,
      "and the hard day still moves its market version"
    );
  }

  test_an_unchanged_market_is_left_out_of_a_delta() {
    const { server, network } = configuredServer("simple");

    server._broadcastState();
    const full = lastState(network);
    this.assertFalse(full.delta, "the first snapshot is full");
    this.assertNotNull(full.resourceMarket, "and carries the whole market");

    // Nothing moved, so the next broadcast is a delta without the market.
    server._broadcastState();
    const quiet = lastState(network);
    this.assertTrue(quiet.delta, "the second snapshot is a delta");
    this.assertNull(quiet.resourceMarket, "an unchanged market is omitted");
    // The pool lives in viewerStats, which every snapshot carries.
    this.assertNotNull(
      quiet.viewerStats.resources.stock,
      "the pool is still shipped inline"
    );
  }

  test_a_trade_reships_the_market_in_the_next_delta() {
    const { server, network } = configuredServer("simple");

    server._broadcastState();
    server._broadcastState();
    const before = lastState(network);
    this.assertNull(before.resourceMarket, "the quiet delta held no market");
    const versionBefore = server.state.snapshot(0).versions.market;
    const poolBefore = server.state.getResourcePool(0).steel;

    this.assertTrue(
      server.state.requestMarketTrade(0, "steel", "buy", 100),
      "a buy is accepted"
    );
    server._broadcastState();
    const after = lastState(network);
    this.assertNotNull(after.resourceMarket, "the changed market is re-shipped");
    this.assertGreater(
      server.state.snapshot(0).versions.market,
      versionBefore,
      "the market version moved"
    );
    this.assertEqual(
      after.viewerStats.resources.stock.steel,
      poolBefore + 100,
      "and the pool rode along in the same delta"
    );
  }

  test_the_server_validates_a_market_trade() {
    const { server } = configuredServer("simple");
    const pool = server.state.getResourcePool(0);
    const steelBefore = pool.steel;
    const stockBefore = server.state.marketStock.get("steel");

    this.assertTrue(
      server.handleOrder(1, { type: "market_trade", side: "buy", resource: "steel", lot: 2000 }),
      "a valid lot is accepted"
    );
    this.assertEqual(pool.steel, steelBefore + 2000, "and the pool moved by the lot");
    this.assertEqual(
      server.state.marketStock.get("steel"),
      stockBefore - 2000,
      "and the world stock paid for it"
    );

    for (const bad of [
      { side: "buy", resource: "steel", lot: 1234 },
      { side: "hold", resource: "steel", lot: 100 },
      { side: "buy", resource: "energy", lot: 100 },
      { side: "buy", resource: "nonsense", lot: 100 },
    ]) {
      this.assertFalse(
        server.handleOrder(1, { type: "market_trade", ...bad }),
        `refused: ${JSON.stringify(bad)}`
      );
    }
    this.assertEqual(pool.steel, steelBefore + 2000, "a refused trade moves no pool");
    this.assertEqual(
      server.state.marketStock.get("steel"),
      stockBefore - 2000,
      "and no stock"
    );
  }

  test_the_hard_server_has_no_market_order() {
    const { server } = configuredServer("hard");
    this.assertFalse(
      server.handleOrder(1, { type: "market_trade", side: "buy", resource: "steel", lot: 2000 }),
      "the hard model refuses the simple market order"
    );
  }
}