diff --git a/.changeset/angry-dryers-open.md b/.changeset/angry-dryers-open.md
new file mode 100644
index 0000000..bbcc9fa
--- /dev/null
+++ b/.changeset/angry-dryers-open.md
@@ -0,0 +1,5 @@
+---
+"sortman": patch
+---
+
+Add description for bucket sort in readme
diff --git a/.changeset/curly-buttons-build.md b/.changeset/curly-buttons-build.md
new file mode 100644
index 0000000..8265508
--- /dev/null
+++ b/.changeset/curly-buttons-build.md
@@ -0,0 +1,5 @@
+---
+"sortman": patch
+---
+
+Fix merge sort's bug
diff --git a/.changeset/fuzzy-adults-play.md b/.changeset/fuzzy-adults-play.md
new file mode 100644
index 0000000..ebab36b
--- /dev/null
+++ b/.changeset/fuzzy-adults-play.md
@@ -0,0 +1,5 @@
+---
+"sortman": patch
+---
+
+Change test func
diff --git a/README.md b/README.md
index 9189b41..9a6f750 100644
--- a/README.md
+++ b/README.md
@@ -54,6 +54,7 @@ console.log(sorted);
 - Quick sort - `SortMan.quick`
 - Selection sort - `SortMan.selection`
 - Shell sort - `SortMan.shell`
+- Bucket sort - `SortMan.bucket`
 
 # Options
 
diff --git a/src/Sort/MergeSort.ts b/src/Sort/MergeSort.ts
index d5728b8..6d0555c 100644
--- a/src/Sort/MergeSort.ts
+++ b/src/Sort/MergeSort.ts
@@ -10,16 +10,27 @@ export class MergeSort extends SortBase {
 		const right = this.core(content.slice(middle));
 		return (() => {
 			const result: SortCoreElement<T> = [];
-			do {
-				const leftElement = left[0] as SortCoreElement<T>[number];
-				const rightElement = right[0] as SortCoreElement<T>[number];
-				if (leftElement.num < rightElement.num) {
-					result.push(left.shift() as SortCoreElement<T>[number]);
+			let i = 0;
+			let l = 0;
+
+			while (i < left.length && l < right.length) {
+				const leftElement = left[i];
+				const rightElement = right[l];
+
+				if (leftElement && rightElement && leftElement.num < rightElement.num) {
+					const element = left[i++];
+					if (element) {
+						result.push(element);
+					}
 				} else {
-					result.push(right.shift() as SortCoreElement<T>[number]);
+					const element = right[l++];
+					if (element) {
+						result.push(element);
+					}
 				}
-			} while (left.length && right.length);
-			return result;
+			}
+
+			return result.concat(left.slice(i)).concat(right.slice(l));
 		})();
 	}
 }
diff --git a/tests/sort.test.ts b/tests/sort.test.ts
index 5c6f9a5..d91ba61 100644
--- a/tests/sort.test.ts
+++ b/tests/sort.test.ts
@@ -2,25 +2,54 @@ import { describe, expect, test } from "@jest/globals";
 import { ignoreSorts, numArrData, objectArrData, sorts } from "./utils";
 import { sortCheck } from "../src/utils/array";
 
+function evalTest(originalData: number[], sortedData: number[], desc?: boolean): boolean {
+	const isSameArr = (() => {
+		const cache = new Map<number, number>();
+
+		for (const element of originalData) {
+			const cachedData = cache.get(element);
+			if (cachedData) {
+				cache.set(element, cachedData + 1);
+			} else {
+				cache.set(element, 1);
+			}
+		}
+
+		for (const [num, count] of cache.entries()) {
+			if (count !== sortedData.filter((value) => value === num).length) {
+				return false;
+			}
+		}
+
+		return true;
+	})() satisfies boolean;
+	return sortCheck(sortedData, desc) && originalData.length === sortedData.length && isSameArr;
+}
+
 for (const { name, algorithm, options } of sorts) {
 	if (!ignoreSorts.includes(name)) {
 		describe(name, () => {
 			describe("Normal test", () => {
 				test("Number array", () => {
 					const result = algorithm.sort(numArrData);
-					expect(sortCheck(result)).toBe(true);
+					expect(evalTest(numArrData, result)).toBe(true);
 				});
 				test("Number array with options", () => {
 					const result = algorithm.sort(numArrData, {
 						func: (e) => e
 					});
-					expect(sortCheck(result)).toBe(true);
+					expect(evalTest(numArrData, result)).toBe(true);
 				});
 				test("Object array", () => {
 					const result = algorithm.sort(objectArrData, {
 						func: (e) => e.num
 					});
-					expect(sortCheck(result.map(({ num }) => num))).toBe(true);
+					expect(
+						evalTest(
+							objectArrData.map(({ num }) => num),
+							result.map(({ num }) => num)
+						)
+					).toBe(true);
 				});
 			});
 			describe("Option test", () => {
@@ -28,7 +57,7 @@ for (const { name, algorithm, options } of sorts) {
 					const result = algorithm.sort(numArrData, {
 						desc: true
 					});
-					expect(sortCheck(result, true)).toBe(true);
+					expect(evalTest(numArrData, result, true)).toBe(true);
 				});
 			});
 			if (options && options.describe) {