From 7ebcbd149123e63a474118b0b554ec7bc5852a14 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Pereira?=
 <77340776+joaopereira12@users.noreply.github.com>
Date: Tue, 30 Jul 2024 05:40:52 +0100
Subject: [PATCH] fix: compare & merge bug GCounter & PNCounter (#73)

Co-authored-by: Oak <me+git@droak.sh>
---
 packages/crdt/src/builtins/GCounter/index.ts | 14 +++---
 packages/crdt/tests/GCounter.test.ts         | 42 ++++++++++++++++
 packages/crdt/tests/PNCounter.test.ts        | 51 ++++++++++++++++++++
 3 files changed, 99 insertions(+), 8 deletions(-)
 create mode 100644 packages/crdt/tests/GCounter.test.ts
 create mode 100644 packages/crdt/tests/PNCounter.test.ts

diff --git a/packages/crdt/src/builtins/GCounter/index.ts b/packages/crdt/src/builtins/GCounter/index.ts
index bf73bb28..e518c359 100644
--- a/packages/crdt/src/builtins/GCounter/index.ts
+++ b/packages/crdt/src/builtins/GCounter/index.ts
@@ -20,12 +20,7 @@ export class GCounter {
   }
 
   compare(peerCounter: GCounter): boolean {
-    for (let key in Object.keys(this.counts)) {
-      if (this.counts[key] > peerCounter.counts[key]) {
-        return false;
-      }
-    }
-    return true;
+    return (this.counts.length === peerCounter.counts.length && Object.keys(this.counts).every(key => this.counts[key] <= peerCounter.counts[key]));
   }
 
   merge(peerCounter: GCounter): void {
@@ -34,8 +29,11 @@ export class GCounter {
       this.counts,
       peerCounter.counts,
     );
+
     Object.keys(temp).forEach((key) => {
-      this.counts[key] = Math.max(this.counts[key], peerCounter.counts[key]);
+      this.counts[key] = Math.max(this.counts[key] || 0, peerCounter.counts[key] || 0);
     });
+
+    this.globalCounter = Object.values(this.counts).reduce((a, b) => a + b, 0);
   }
-}
+}
\ No newline at end of file
diff --git a/packages/crdt/tests/GCounter.test.ts b/packages/crdt/tests/GCounter.test.ts
new file mode 100644
index 00000000..7aecf6e6
--- /dev/null
+++ b/packages/crdt/tests/GCounter.test.ts
@@ -0,0 +1,42 @@
+import { describe, test, expect, beforeEach } from "vitest";
+import { GCounter } from "../src/builtins/GCounter";
+
+describe("G-Counter Tests", () => {
+    let set1: GCounter;
+
+    beforeEach(() => {
+        set1 = new GCounter({ "node1": 5, "node2": 10});
+    });
+
+    test("Test Initial Values", () => {
+        expect(set1.value()).toBe(15);
+    });
+
+    test("Test Increment", () => {
+        set1.increment("node1", 10);
+        set1.increment("node2", 5);
+
+        expect(set1.value()).toBe(30);
+    });
+
+    test("Test Compare", () => {
+        let set2 = new GCounter({ "node1": 5, "node2": 10});
+        let set3 = new GCounter({ "node1": 5, "node2": 10, "node3": 15 });
+
+        expect(set1.compare(set2)).toBe(true);
+        set1.increment("node1", 5);
+        expect(set1.compare(set2)).toBe(false);
+        expect(set1.compare(set3)).toBe(false);
+    });
+
+    test("Test Merge", () => {
+        let set2 = new GCounter({ "node1": 3, "node2": 10});
+        let set3 = new GCounter({ "node1": 5, "node3": 15}); 
+        
+        expect(set1.counts).toEqual({"node1": 5, "node2": 10});
+        set2.merge(set1);
+        expect(set2.counts).toEqual({"node1": 5, "node2": 10});
+        set1.merge(set3);
+        expect(set1.counts).toEqual({"node1": 5, "node2": 10, "node3": 15});
+    });
+});
\ No newline at end of file
diff --git a/packages/crdt/tests/PNCounter.test.ts b/packages/crdt/tests/PNCounter.test.ts
new file mode 100644
index 00000000..89c6819f
--- /dev/null
+++ b/packages/crdt/tests/PNCounter.test.ts
@@ -0,0 +1,51 @@
+import { describe, test, expect, beforeEach, afterEach } from "vitest";
+import { PNCounter } from "../src/builtins/PNCounter";
+import { GCounter } from "../src/builtins/GCounter";
+
+describe("PN-Counter Tests", () => {
+    let set1: PNCounter;
+    let set2: PNCounter;
+
+    beforeEach(() => {
+        set1 = new PNCounter(new GCounter({ "node1": 5, "node2": 10, "node3": 15 }), new GCounter({ "node1": 3, "node2": 4, "node3": 3 }));
+        set2 = new PNCounter(new GCounter({ "node1": 5, "node2": 10, "node3": 15 }), new GCounter({ "node1": 3, "node2": 4, "node3": 3 }));
+    });
+
+    test("Test Initial Value", () => {
+        expect(set1.value()).toBe(20);
+        expect(set2.value()).toBe(20);
+    });
+
+    test("Test Increment", () => {
+        set1.increment("node1",10);
+        set2.increment("node1",20);
+        expect(set1.value()).toBe(30);
+        expect(set2.value()).toBe(40);
+    });
+
+    test("Test Decrement", () => {
+        set1.decrement("node1",10);
+        set2.decrement("node1",20);
+        expect(set1.value()).toBe(10);
+        expect(set2.value()).toBe(0);
+    });
+
+    test("Test Compare", () => {
+        expect(set1.compare(set2)).toBe(true);
+        set1.decrement("node1",10);
+        expect(set1.compare(set2)).toBe(false);
+        set2.decrement("node1",10);
+        expect(set1.compare(set2)).toBe(true);
+    });
+
+    test("Test Merge", () => {
+        set1.increment("node1",10);
+        set2.decrement("node2",5);
+        expect(set1.compare(set2)).toBe(false);
+        expect(set2.compare(set1)).toBe(false); 
+        set1.merge(set2);
+        set2.merge(set1);
+        expect(set1.compare(set2)).toBe(true);
+        expect(set2.compare(set1)).toBe(true);        
+    });
+});
\ No newline at end of file