6 files changed, 485 insertions, 27 deletions

diff --git a/service/src/main/java/market/guess/service/LocalGuessMarketContext.java b/service/src/main/java/market/guess/service/LocalGuessMarketContext.java
index 909a808..f04324b 100644
--- a/service/src/main/java/market/guess/service/LocalGuessMarketContext.java
+++ b/service/src/main/java/market/guess/service/LocalGuessMarketContext.java
@@ -10,6 +10,7 @@ import market.guess.model.event.EventDetailDTO;
 import market.guess.service.catalog.infrastructure.MarketContext;
 import market.guess.service.domain.Order;
 import market.guess.service.fulfillment.FulfillmentContext;
+import market.guess.service.helpers.BigDecimalOptions;
 import market.guess.service.helpers.InstantOptions;
 import market.guess.service.matching.MatchingEngine;
 import market.guess.service.risk.RiskEngine;
@@ -55,6 +56,20 @@ public final class LocalGuessMarketContext implements GuessMarketContext {
 
     var rawTrades = matching.match(order);
     var trades = fulfillment.fulfill(user, order, rawTrades);
+
+    var totalSharesCost =
+        trades.stream()
+            .map(t -> t.sharesCost())
+            .reduce(BigDecimalOptions.ZERO_MONEY, BigDecimal::add);
+    var totalCommission =
+        trades.stream()
+            .map(t -> t.commission())
+            .reduce(BigDecimalOptions.ZERO_MONEY, BigDecimal::add);
+    var totalPaid =
+        trades.stream()
+            .map(t -> t.totalPaid())
+            .reduce(BigDecimalOptions.ZERO_MONEY, BigDecimal::add);
+
     return Result.ok(
         new PurchaseReceiptDTO(
             trades.stream()
@@ -65,8 +80,11 @@ public final class LocalGuessMarketContext implements GuessMarketContext {
                             t.buyerUserName(),
                             t.marketName(),
                             String.valueOf(t.quantity()),
-                            t.totalPaid().toPlainString()))
+                            t.sharesCost().toPlainString()))
                 .toList(),
+            totalSharesCost.toPlainString(),
+            totalCommission.toPlainString(),
+            totalPaid.toPlainString(),
             event.toMarketState()));
   }
 
diff --git a/service/src/main/java/market/guess/service/catalog/infrastructure/MarketContext.java b/service/src/main/java/market/guess/service/catalog/infrastructure/MarketContext.java
index cb2b467..5fc2e24 100644
--- a/service/src/main/java/market/guess/service/catalog/infrastructure/MarketContext.java
+++ b/service/src/main/java/market/guess/service/catalog/infrastructure/MarketContext.java
@@ -67,15 +67,22 @@ public final class MarketContext {
           GSON.toJson(new Wrapper(events.getAll(), users.getAll())),
           StandardCharsets.UTF_8);
     } catch (Exception e) {
-      throw new GuessMarketException("Failed to sove the file.");
+      throw new GuessMarketException("Failed to save state to " + target + ": " + e.getMessage());
     }
   }
 
   public void load(Path path) throws GuessMarketException {
+    var target = withJsonExtension(path);
+    if (!Files.isRegularFile(target)) {
+      throw new GuessMarketException("State file not found: " + target);
+    }
     try {
       var wrapper =
           GSON.fromJson(
-              Files.readString(withJsonExtension(path), StandardCharsets.UTF_8), Wrapper.class);
+              Files.readString(target, StandardCharsets.UTF_8), Wrapper.class);
+      if (wrapper == null || wrapper.events() == null) {
+        throw new GuessMarketException("State file contains invalid or empty data.");
+      }
       events.clear();
       users.clear();
 
@@ -88,14 +95,15 @@ public final class MarketContext {
       }
 
     } catch (JsonSyntaxException e) {
-      throw new GuessMarketException("The JSON file is malformed.");
+      throw new GuessMarketException("The state file is malformed JSON: " + e.getMessage());
     } catch (IOException e) {
-      throw new GuessMarketException("Unable the file.");
+      throw new GuessMarketException("Unable to read state file: " + e.getMessage());
     }
   }
 
   private static Path withJsonExtension(Path path) {
+    if (path == null) return null;
     var name = path.getFileName().toString();
-    return name.endsWith(".json") ? path : path.resolveSibling(name + ".json");
+    return name.toLowerCase().endsWith(".json") ? path : path.resolveSibling(name + ".json");
   }
 }
diff --git a/service/src/main/java/market/guess/service/catalog/infrastructure/mapper/v1/EventMapperV1.java b/service/src/main/java/market/guess/service/catalog/infrastructure/mapper/v1/EventMapperV1.java
index f45eb46..b9c43bb 100644
--- a/service/src/main/java/market/guess/service/catalog/infrastructure/mapper/v1/EventMapperV1.java
+++ b/service/src/main/java/market/guess/service/catalog/infrastructure/mapper/v1/EventMapperV1.java
@@ -19,8 +19,8 @@ public final class EventMapperV1 implements Mapper<GMEvent, Event> {
     return new Event(
         getEventKey(source),
         source.getId(),
-        joinName(source.getName()),
-        source.getDescription(),
+        joinName(source.getName()).trim(),
+        source.getDescription() != null ? source.getDescription().trim() : "",
         source.getComision().getValue(),
         getTiming(source.getComision().getType()),
         new LmsrTradingMechanism(source.getGMMethod().getGMLMSR().getB(), options.size()),
@@ -38,17 +38,20 @@ public final class EventMapperV1 implements Mapper<GMEvent, Event> {
   }
 
   private static CommissionTiming getTiming(String type) throws IllegalArgumentException {
-    return switch (type) {
+    if (type == null) throw new IllegalArgumentException("Commission type cannot be null");
+    return switch (type.toLowerCase().trim()) {
       case "on-close" -> CommissionTiming.ON_CLOSE;
       case "on-purchase" -> CommissionTiming.ON_PURCHASE;
-      default -> throw new IllegalArgumentException("Unknown comision type: " + type);
+      default -> throw new IllegalArgumentException("Unknown commission type: " + type);
     };
   }
 
   private static List<Market> getOptions(GMEvent x) {
-    var ret = new ArrayList<Market>(x.getGMOptions().getGMOption().size());
-    for (var i = 0; i < x.getGMOptions().getGMOption().size(); i++) {
-      ret.add(new Market(getEventKey(x) + ":" + i, x.getGMOptions().getGMOption().get(i)));
+    var raw = x.getGMOptions().getGMOption();
+    var ret = new ArrayList<Market>(raw.size());
+    for (var i = 0; i < raw.size(); i++) {
+      var opt = raw.get(i);
+      ret.add(new Market(getEventKey(x) + ":" + i, opt != null ? opt.trim() : ""));
     }
     return ret;
   }
diff --git a/service/src/main/java/market/guess/service/catalog/infrastructure/provider/v1/XMLLoaderV1.java b/service/src/main/java/market/guess/service/catalog/infrastructure/provider/v1/XMLLoaderV1.java
index bcae787..44e1c7f 100644
--- a/service/src/main/java/market/guess/service/catalog/infrastructure/provider/v1/XMLLoaderV1.java
+++ b/service/src/main/java/market/guess/service/catalog/infrastructure/provider/v1/XMLLoaderV1.java
@@ -2,8 +2,10 @@ package market.guess.service.catalog.infrastructure.provider.v1;
 
 import jakarta.xml.bind.JAXBContext;
 import jakarta.xml.bind.JAXBException;
+import java.math.BigDecimal;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.ArrayList;
 import market.guess.api.CatalogContext;
 import market.guess.api.LoadResult;
 import market.guess.api.Result;
@@ -12,6 +14,7 @@ import market.guess.service.catalog.infrastructure.provider.Loader;
 import market.guess.service.catalog.infrastructure.repository.EventRepository;
 import market.guess.service.catalog.infrastructure.repository.UserRepository;
 import market.guess.service.catalog.model.v1.GuessMarket;
+import market.guess.service.domain.Event;
 import market.guess.service.domain.User;
 
 public final class XMLLoaderV1 implements Loader {
@@ -35,19 +38,23 @@ public final class XMLLoaderV1 implements Loader {
     try {
       context = JAXBContext.newInstance(GuessMarket.class);
     } catch (JAXBException e) {
-      throw new IllegalStateException();
+      throw new IllegalStateException("Failed to initialize JAXB context: " + e.getMessage(), e);
     }
   }
 
   @Override
   public Result<LoadResult> load(Path path) {
+    if (path == null) {
+      return Result.error("INVALID_PATH", "File path cannot be null.");
+    }
+
     if (!Files.isRegularFile(path)) {
-      return Result.error("FILE_NOT_FOUND", "No such file.");
+      return Result.error("FILE_NOT_FOUND", "No such file: " + path);
     }
 
     if (path.getFileName() == null
         || !path.getFileName().toString().toLowerCase().endsWith(".xml")) {
-      return Result.error("NOT_XML", "The file must be an XML.");
+      return Result.error("NOT_XML", "The file must have a .xml extension.");
     }
 
     try (var stream = Files.newInputStream(path)) {
@@ -59,21 +66,34 @@ public final class XMLLoaderV1 implements Loader {
         return Result.error(validation.getMessage(), validation.getDetails());
       }
 
+      var domainEvents = new ArrayList<Event>();
       for (var event : seed.getGMEvents().getGMEvent()) {
-        eventRepository.add(mapper.toDomain(event));
+        domainEvents.add(mapper.toDomain(event));
+      }
+
+      eventRepository.clear();
+      userRepository.clear();
+
+      for (var domainEvent : domainEvents) {
+        eventRepository.add(domainEvent);
       }
 
-      userRepository.add(new User("Tester", 500));
+      userRepository.add(new User("Tester", new BigDecimal("500.00")));
 
       return Result.ok(new LoadResult(path.toString(), eventRepository.getAll().size()));
+    } catch (JAXBException e) {
+      var cause =
+          e.getLinkedException() != null ? e.getLinkedException().getMessage() : e.getMessage();
+      return Result.error(
+          "XML_PARSE_ERROR",
+          "The XML file is malformed or invalid: " + (cause != null ? cause : e.getMessage()));
     } catch (Exception e) {
-      return Result.error("UNREADABLE", "The file could not be read.");
+      return Result.error("UNREADABLE", "The file could not be read: " + e.getMessage());
     }
   }
 
   @Override
   public Result<LoadResult> seed(CatalogContext context) {
-    // TODO Auto-generated method stub
     throw new UnsupportedOperationException("Unimplemented method 'seed'");
   }
 }
diff --git a/service/src/main/java/market/guess/service/catalog/infrastructure/provider/v1/XMLValidatorV1.java b/service/src/main/java/market/guess/service/catalog/infrastructure/provider/v1/XMLValidatorV1.java
index 567558a..5a4e5ea 100644
--- a/service/src/main/java/market/guess/service/catalog/infrastructure/provider/v1/XMLValidatorV1.java
+++ b/service/src/main/java/market/guess/service/catalog/infrastructure/provider/v1/XMLValidatorV1.java
@@ -9,27 +9,93 @@ public final class XMLValidatorV1 {
   private static final int MAX_COMMISSION = 90;
 
   public Result<Void> validate(GuessMarket seed) {
+    if (seed == null || seed.getGMEvents() == null || seed.getGMEvents().getGMEvent() == null) {
+      return Result.error("INVALID_XML", "The XML file contains no GM-events element.");
+    }
 
-    var seenIds = new HashSet<Integer>();
-    var duplicated = new HashSet<Integer>();
+    var events = seed.getGMEvents().getGMEvent();
+    if (events.isEmpty()) {
+      return Result.error("EMPTY_EVENTS", "The XML file does not contain any events.");
+    }
 
-    for (var e : seed.getGMEvents().getGMEvent()) {
+    var seenIds = new HashSet<Integer>();
 
-      if (!seenIds.add(e.getId()) && duplicated.add(e.getId())) {
+    for (var e : events) {
+      // 1. Event ID must be positive integer (> 0)
+      if (e.getId() <= 0) {
+        return Result.error(
+            "INVALID_ID",
+            "Event ID must be a positive integer (> 0), found: " + e.getId());
+      }
+      if (!seenIds.add(e.getId())) {
         return Result.error(
             "DUPLICATE_ID",
-            "Event id " + e.getId() + " appears more than once, every event id must be unique.");
+            "Event ID " + e.getId() + " appears more than once. Every event ID must be unique.");
       }
 
+      // 2. Event name must not be empty
+      if (e.getName() == null || e.getName().isEmpty() || String.join(" ", e.getName()).isBlank()) {
+        return Result.error("MISSING_NAME", "Event ID " + e.getId() + " has an empty name.");
+      }
+
+      // 3. Event description must not be empty
+      if (e.getDescription() == null || e.getDescription().isBlank()) {
+        return Result.error("MISSING_DESCRIPTION", "Event ID " + e.getId() + " has an empty description.");
+      }
+
+      // 4. Commission validation
+      if (e.getComision() == null) {
+        return Result.error("MISSING_COMMISSION", "Event ID " + e.getId() + " is missing commission.");
+      }
       var pct = e.getComision().getValue();
       if (pct < MIN_COMMISSION || pct > MAX_COMMISSION) {
         return Result.error(
             "COMMISSION_OUT_OF_RANGE",
-            "Commission is %d%%, it must be between %d%% and %d%%."
-                .formatted(pct, MIN_COMMISSION, MAX_COMMISSION));
+            "Event ID " + e.getId() + " commission is " + pct + "%. It must be between " + MIN_COMMISSION + "% and " + MAX_COMMISSION + "%.");
+      }
+
+      var type = e.getComision().getType();
+      if (type == null || (!type.equalsIgnoreCase("on-close") && !type.equalsIgnoreCase("on-purchase"))) {
+        return Result.error(
+            "INVALID_COMMISSION_TYPE",
+            "Event ID " + e.getId() + " has invalid commission type '" + type + "'. Must be 'on-close' or 'on-purchase'.");
+      }
+
+      // 5. GM-options validation (exactly 2 options for Exercise 1)
+      if (e.getGMOptions() == null || e.getGMOptions().getGMOption() == null) {
+        return Result.error("MISSING_OPTIONS", "Event ID " + e.getId() + " is missing GM-options.");
+      }
+      var options = e.getGMOptions().getGMOption();
+      if (options.size() != 2) {
+        return Result.error(
+            "INVALID_OPTIONS_COUNT",
+            "Event ID " + e.getId() + " must have exactly 2 options for Exercise 1, but found " + options.size() + ".");
+      }
+      var opt0 = options.get(0) == null ? "" : options.get(0).trim();
+      var opt1 = options.get(1) == null ? "" : options.get(1).trim();
+      if (opt0.isEmpty() || opt1.isEmpty()) {
+        return Result.error("EMPTY_OPTION", "Event ID " + e.getId() + " has an empty option name.");
+      }
+      if (opt0.equalsIgnoreCase(opt1)) {
+        return Result.error("DUPLICATE_OPTION", "Event ID " + e.getId() + " has duplicate option names: '" + opt0 + "'.");
+      }
+
+      // 6. GM-method and LMSR validation
+      if (e.getGMMethod() == null) {
+        return Result.error("MISSING_METHOD", "Event ID " + e.getId() + " is missing GM-method.");
+      }
+      if (e.getGMMethod().getGMLMSR() == null) {
+        return Result.error("INVALID_METHOD", "Event ID " + e.getId() + " must use LMSR trading method in Exercise 1.");
+      }
+      var b = e.getGMMethod().getGMLMSR().getB();
+      if (b <= 0) {
+        return Result.error(
+            "INVALID_LIQUIDITY",
+            "Event ID " + e.getId() + " has invalid liquidity b=" + b + ". b must be a positive integer (> 0).");
       }
     }
 
     return Result.ok();
   }
 }
+
diff --git a/service/src/test/java/market/guess/service/Ex1FullTest.java b/service/src/test/java/market/guess/service/Ex1FullTest.java
new file mode 100644
index 0000000..6718142
--- /dev/null
+++ b/service/src/test/java/market/guess/service/Ex1FullTest.java
@@ -0,0 +1,343 @@
+package market.guess.service;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.math.BigDecimal;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.time.Instant;
+import java.util.List;
+import market.guess.api.CommissionTiming;
+import market.guess.model.event.EventStatus;
+import market.guess.service.catalog.LocalCatalogContext;
+import market.guess.service.catalog.infrastructure.MarketContext;
+import market.guess.service.catalog.infrastructure.mapper.v1.EventMapperV1;
+import market.guess.service.catalog.infrastructure.provider.v1.XMLLoaderV1;
+import market.guess.service.catalog.infrastructure.provider.v1.XMLValidatorV1;
+import market.guess.service.catalog.infrastructure.repository.InMemoryEventRepository;
+import market.guess.service.catalog.infrastructure.repository.InMemoryUserRepository;
+import market.guess.service.domain.Event;
+import market.guess.service.domain.Market;
+import market.guess.service.domain.User;
+import market.guess.service.fulfillment.LocalFulfillmentContext;
+import market.guess.service.helpers.BigDecimalOptions;
+import market.guess.service.ledger.LedgerContext;
+import market.guess.service.matching.LocalMatchingEngine;
+import market.guess.service.mechanism.LmsrTradingMechanism;
+import market.guess.service.risk.LocalRiskEngine;
+import market.guess.service.settlement.LocalSettlementContext;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class Ex1FullTest {
+
+  private InMemoryEventRepository eventRepo;
+  private InMemoryUserRepository userRepo;
+  private MarketContext marketContext;
+  private XMLLoaderV1 loader;
+  private XMLValidatorV1 validator;
+  private LocalCatalogContext catalog;
+  private LocalGuessMarketContext guessMarket;
+  private LedgerContext ledgerContext;
+  private LocalSettlementContext settlementContext;
+
+  @BeforeEach
+  public void setUp() {
+    eventRepo = new InMemoryEventRepository();
+    userRepo = new InMemoryUserRepository();
+    marketContext = new MarketContext(eventRepo, userRepo);
+    validator = new XMLValidatorV1();
+    loader = new XMLLoaderV1(eventRepo, userRepo, new EventMapperV1(), validator);
+    catalog = new LocalCatalogContext(loader, marketContext, eventRepo);
+    ledgerContext = new LedgerContext(userRepo, java.time.Clock.systemUTC());
+    settlementContext = new LocalSettlementContext(ledgerContext);
+    guessMarket =
+        new LocalGuessMarketContext(
+            marketContext,
+            new LocalRiskEngine(),
+            new LocalMatchingEngine(java.time.Clock.systemUTC()),
+            new LocalFulfillmentContext(ledgerContext),
+            settlementContext);
+  }
+
+  @Test
+  public void testLmsrMathCalculations() {
+    var lmsr = new LmsrTradingMechanism(100, 2);
+
+    // Initial prices should be 0.50 and 0.50
+    var initialPrices = lmsr.prices();
+    assertEquals(new BigDecimal("0.50"), initialPrices[0]);
+    assertEquals(new BigDecimal("0.50"), initialPrices[1]);
+
+    // Initial max loss / subsidy = 100 * ln(2) = 69.31
+    assertEquals(new BigDecimal("69.31"), lmsr.maxLoss());
+
+    // Buy 100 shares of option 0 (YES)
+    var dummyEvent =
+        new Event(
+            "1",
+            1,
+            "Test Event",
+            "Desc",
+            0,
+            CommissionTiming.ON_PURCHASE,
+            lmsr,
+            EventStatus.ACTIVE,
+            List.of(new Market("1:0", "YES"), new Market("1:1", "NO")),
+            "Tester");
+
+    var trades = lmsr.buy(dummyEvent, dummyEvent.getMarkets().get(0), Instant.now(), 100);
+    assertEquals(1, trades.size());
+    assertEquals(100, trades.get(0).quantity());
+    assertEquals(new BigDecimal("62.01"), trades.get(0).sharesCost());
+
+    // Price after 100 shares of YES should be ~0.73 and ~0.27
+    var pricesAfter = lmsr.prices();
+    assertEquals(new BigDecimal("0.73"), pricesAfter[0]);
+    assertEquals(new BigDecimal("0.27"), pricesAfter[1]);
+  }
+
+  @Test
+  public void testXmlLoadingAndAtomicity() {
+    var xmlPath = Path.of("test-data/ex-1/multiple.xml");
+    assertTrue(Files.exists(xmlPath), "test-data/ex-1/multiple.xml must exist");
+
+    var result = catalog.loadEvents(xmlPath);
+    assertTrue(result.isSuccess(), "Loading multiple.xml should succeed");
+    assertEquals(3, result.getData().eventsLoaded());
+    assertEquals(3, eventRepo.getAll().size());
+
+    // Re-loading multiple.xml should replace, NOT accumulate (size must remain 3)
+    var reloadResult = catalog.loadEvents(xmlPath);
+    assertTrue(reloadResult.isSuccess());
+    assertEquals(3, eventRepo.getAll().size());
+
+    // Loading non-existent file should fail and preserve 3 events
+    var failResult = catalog.loadEvents(Path.of("non_existent_file.xml"));
+    assertFalse(failResult.isSuccess());
+    assertEquals(3, eventRepo.getAll().size());
+
+    // Loading non-xml file should fail and preserve 3 events
+    var notXmlResult = catalog.loadEvents(Path.of("README.md"));
+    assertFalse(notXmlResult.isSuccess());
+    assertEquals(3, eventRepo.getAll().size());
+  }
+
+  @Test
+  public void testPlaceOrderWithOnPurchaseCommission() {
+    var xmlPath = Path.of("test-data/ex-1/multiple.xml");
+    catalog.loadEvents(xmlPath);
+
+    // Event 1 has 5% commission on-purchase
+    var event1 = eventRepo.get("1").orElseThrow();
+    assertEquals(5, event1.getCommissionPercent());
+    assertEquals(CommissionTiming.ON_PURCHASE, event1.getCommissionTiming());
+
+    var option0Key = event1.getMarkets().get(0).getKey();
+    var buyResult = guessMarket.placeOrder("Tester", "1", option0Key, new BigDecimal("0.50"), 100);
+
+    assertTrue(buyResult.isSuccess());
+    var receipt = buyResult.getData();
+    assertNotNull(receipt);
+    assertEquals("62.01", receipt.sharesCost());
+    assertEquals("3.10", receipt.commissionPaid()); // 5% of 62.01 = 3.1005 -> 3.10
+    assertEquals("65.11", receipt.totalPaid()); // 62.01 + 3.10 = 65.11
+
+    // History should contain 1 trade
+    assertEquals(1, event1.getHistory().size());
+    assertEquals("62.01", event1.getHistory().get(0).pricePaid());
+  }
+
+  @Test
+  public void testSettleEventWithOnCloseCommission() {
+    var xmlPath = Path.of("test-data/ex-1/multiple.xml");
+    catalog.loadEvents(xmlPath);
+
+    // Event 2 has 15% commission on-close, b=50
+    var event2 = eventRepo.get("2").orElseThrow();
+    assertEquals(15, event2.getCommissionPercent());
+    assertEquals(CommissionTiming.ON_CLOSE, event2.getCommissionTiming());
+
+    var option0Key = event2.getMarkets().get(0).getKey();
+    // Buy 50 shares of Argentina
+    var buyResult = guessMarket.placeOrder("Tester", "2", option0Key, new BigDecimal("0.50"), 50);
+    assertTrue(buyResult.isSuccess());
+    var receipt = buyResult.getData();
+    // On purchase commission is 0.00
+    assertEquals("0.00", receipt.commissionPaid());
+
+    // Now settle event choosing option 0 as winner
+    var settleResult = guessMarket.settleEvent("Tester", "2", option0Key);
+    assertTrue(settleResult.isSuccess());
+
+    var detail = settleResult.getData();
+    assertEquals(EventStatus.SETTLED, detail.summary().status());
+    assertEquals(event2.getMarkets().get(0).getName(), detail.settledMarket());
+
+    // 50 winning shares @ $1 gross = $50.00. 15% commission = $7.50. Net payout = $42.50.
+    assertEquals(new BigDecimal("7.50"), event2.getCommission());
+  }
+
+  @Test
+  public void testStateSaveAndRestoreBonusRoundTrip() throws Exception {
+    var xmlPath = Path.of("test-data/ex-1/multiple.xml");
+    catalog.loadEvents(xmlPath);
+
+    // Trade on event 1
+    var optKey = eventRepo.get("1").orElseThrow().getMarkets().get(0).getKey();
+    guessMarket.placeOrder("Tester", "1", optKey, new BigDecimal("0.50"), 100);
+
+    // Save to temp file
+    var tempDir = Files.createTempDirectory("gm_test_save");
+    var savePath = tempDir.resolve("snapshot");
+
+    var saveRes = catalog.saveState(savePath);
+    assertTrue(saveRes.isSuccess(), "Saving state should succeed");
+    assertTrue(Files.exists(tempDir.resolve("snapshot.json")), "snapshot.json must exist");
+
+    // Clear repositories
+    eventRepo.clear();
+    userRepo.clear();
+    assertEquals(0, eventRepo.getAll().size());
+
+    // Restore from path (without extension)
+    var restoreRes = catalog.restoreState(savePath);
+    assertTrue(restoreRes.isSuccess(), "Restoring state should succeed");
+    assertEquals(3, restoreRes.getData().eventsLoaded());
+    assertEquals(3, eventRepo.getAll().size());
+
+    var restoredEvent1 = eventRepo.get("1").orElseThrow();
+    assertEquals(1, restoredEvent1.getTrades().size());
+    assertEquals(100, restoredEvent1.getTrades().get(0).quantity());
+    assertEquals(new BigDecimal("62.01"), restoredEvent1.getTrades().get(0).sharesCost());
+  }
+
+  @Test
+  public void testXmlValidationRules() throws Exception {
+    var tempDir = Files.createTempDirectory("gm_xml_val_test");
+
+    // 1. Commission > 90
+    var xmlInvalidComm =
+        """
+        <?xml version="1.0" encoding="UTF-8"?>
+        <Guess-Market>
+          <GM-events>
+            <GM-event name="High Comm">
+              <id>1</id>
+              <description>Desc</description>
+              <comision type="on-purchase">95</comision>
+              <GM-options>
+                <GM-option>Yes</GM-option>
+                <GM-option>No</GM-option>
+              </GM-options>
+              <GM-method><GM-LMSR><b>100</b></GM-LMSR></GM-method>
+            </GM-event>
+          </GM-events>
+        </Guess-Market>
+        """;
+    var p1 = tempDir.resolve("high_comm.xml");
+    Files.writeString(p1, xmlInvalidComm);
+    var res1 = catalog.loadEvents(p1);
+    assertFalse(res1.isSuccess());
+    assertTrue(res1.getDetails().contains("between 0% and 90%"));
+
+    // 2. Duplicate Event IDs
+    var xmlDupId =
+        """
+        <?xml version="1.0" encoding="UTF-8"?>
+        <Guess-Market>
+          <GM-events>
+            <GM-event name="Event 1">
+              <id>1</id>
+              <description>Desc 1</description>
+              <comision type="on-purchase">10</comision>
+              <GM-options><GM-option>Yes</GM-option><GM-option>No</GM-option></GM-options>
+              <GM-method><GM-LMSR><b>100</b></GM-LMSR></GM-method>
+            </GM-event>
+            <GM-event name="Event 2">
+              <id>1</id>
+              <description>Desc 2</description>
+              <comision type="on-close">10</comision>
+              <GM-options><GM-option>Yes</GM-option><GM-option>No</GM-option></GM-options>
+              <GM-method><GM-LMSR><b>100</b></GM-LMSR></GM-method>
+            </GM-event>
+          </GM-events>
+        </Guess-Market>
+        """;
+    var p2 = tempDir.resolve("dup_id.xml");
+    Files.writeString(p2, xmlDupId);
+    var res2 = catalog.loadEvents(p2);
+    assertFalse(res2.isSuccess());
+    assertTrue(res2.getDetails().contains("Every event ID must be unique"));
+
+    // 3. Three options (must be exactly 2 for Ex1)
+    var xml3Opts =
+        """
+        <?xml version="1.0" encoding="UTF-8"?>
+        <Guess-Market>
+          <GM-events>
+            <GM-event name="Three Options">
+              <id>1</id>
+              <description>Desc</description>
+              <comision type="on-purchase">10</comision>
+              <GM-options>
+                <GM-option>Opt 1</GM-option>
+                <GM-option>Opt 2</GM-option>
+                <GM-option>Opt 3</GM-option>
+              </GM-options>
+              <GM-method><GM-LMSR><b>100</b></GM-LMSR></GM-method>
+            </GM-event>
+          </GM-events>
+        </Guess-Market>
+        """;
+    var p3 = tempDir.resolve("three_opts.xml");
+    Files.writeString(p3, xml3Opts);
+    var res3 = catalog.loadEvents(p3);
+    assertFalse(res3.isSuccess());
+    assertTrue(res3.getDetails().contains("must have exactly 2 options"));
+
+    // 4. Invalid liquidity b <= 0
+    var xmlBadB =
+        """
+        <?xml version="1.0" encoding="UTF-8"?>
+        <Guess-Market>
+          <GM-events>
+            <GM-event name="Bad B">
+              <id>1</id>
+              <description>Desc</description>
+              <comision type="on-purchase">10</comision>
+              <GM-options><GM-option>Yes</GM-option><GM-option>No</GM-option></GM-options>
+              <GM-method><GM-LMSR><b>0</b></GM-LMSR></GM-method>
+            </GM-event>
+          </GM-events>
+        </Guess-Market>
+        """;
+    var p4 = tempDir.resolve("bad_b.xml");
+    Files.writeString(p4, xmlBadB);
+    var res4 = catalog.loadEvents(p4);
+    assertFalse(res4.isSuccess());
+    assertTrue(res4.getDetails().contains("positive integer"));
+
+    // 5. Invalid commission type
+    var xmlBadCommType =
+        """
+        <?xml version="1.0" encoding="UTF-8"?>
+        <Guess-Market>
+          <GM-events>
+            <GM-event name="Bad Comm Type">
+              <id>1</id>
+              <description>Desc</description>
+              <comision type="invalid-type">10</comision>
+              <GM-options><GM-option>Yes</GM-option><GM-option>No</GM-option></GM-options>
+              <GM-method><GM-LMSR><b>100</b></GM-LMSR></GM-method>
+            </GM-event>
+          </GM-events>
+        </Guess-Market>
+        """;
+    var p5 = tempDir.resolve("bad_comm_type.xml");
+    Files.writeString(p5, xmlBadCommType);
+    var res5 = catalog.loadEvents(p5);
+    assertFalse(res5.isSuccess());
+    assertTrue(res5.getDetails().contains("Must be 'on-close' or 'on-purchase'"));
+  }
+}