diff --git a/spec/utils.ts b/spec/utils.ts
index e792ff5..2db95e3 100644
--- a/spec/utils.ts
+++ b/spec/utils.ts
@@ -1,59 +1,39 @@
-import { splitBufferBundle } from "../lib/utils";
-import type { BundleUnit } from "../lib/schemas";
+import { processDate, removeHidden } from "../lib/utils";
 
-describe("splitBufferBundle", () => {
-	it("should split the bundle in language-organized files buffers and normal files with valid bundleUnit passed", () => {
-		const zeroBuffer = Buffer.alloc(0);
-		const payload: BundleUnit = {
-			"en.lproj/thumbnail@2x.png": zeroBuffer,
-			"de.lproj/background@2x.png": zeroBuffer,
-			"it.lproj/thumbnail@2x.png": zeroBuffer,
-			"thumbnail@2x.png": zeroBuffer,
-			"background.png": zeroBuffer,
-		};
+describe("Utils", () => {
+	describe("removeHidden", () => {
+		it("should remove files that start with dot", () => {
+			const filesList = [
+				"a.png",
+				"b.png",
+				".DS_Store",
+				"not_the_droids_you_are_looking_for.txt",
+			];
 
-		const result = splitBufferBundle(payload);
-
-		expect(result).toBeDefined();
-		expect(result.length).toBe(2);
-		expect(result[0]).toEqual({
-			"en.lproj": {
-				"thumbnail@2x.png": zeroBuffer,
-			},
-			"de.lproj": {
-				"background@2x.png": zeroBuffer,
-			},
-			"it.lproj": {
-				"thumbnail@2x.png": zeroBuffer,
-			},
-		});
-		expect(result[1]).toEqual({
-			"thumbnail@2x.png": zeroBuffer,
-			"background.png": zeroBuffer,
+			expect(removeHidden(filesList)).toEqual([
+				"a.png",
+				"b.png",
+				"not_the_droids_you_are_looking_for.txt",
+			]);
 		});
 	});
 
-	it("should return empty partitionedBufferBundle if BundleUnit is empty object", () => {
-		const result = splitBufferBundle({});
+	describe("processDate", () => {
+		it("should throw Invalid date if args[0] is not a date", () => {
+			//@ts-expect-error
+			expect(() => processDate(5)).toThrow("Invalid date");
+			//@ts-expect-error
+			expect(() => processDate({})).toThrow("Invalid date");
+			//@ts-expect-error
+			expect(() => processDate("ciao")).toThrow("Invalid date");
+			//@ts-expect-error
+			expect(() => processDate(true)).toThrow("Invalid date");
+		});
 
-		expect(result).toBeDefined();
-		expect(result.length).toBe(2);
-		expect(result[0]).toEqual({});
-		expect(result[1]).toEqual({});
-	});
-
-	it("should return empty partitionedBufferBundle if BundleUnit is undefined", () => {
-		const resultUndefined = splitBufferBundle(undefined);
-		const resultNull = splitBufferBundle(null);
-
-		expect(resultUndefined).toBeDefined();
-		expect(resultUndefined.length).toBe(2);
-		expect(resultUndefined[0]).toEqual({});
-		expect(resultUndefined[1]).toEqual({});
-
-		expect(resultNull).toBeDefined();
-		expect(resultNull.length).toBe(2);
-		expect(resultNull[0]).toEqual({});
-		expect(resultNull[1]).toEqual({});
+		it("should convert a Date object to a valid W3C date", () => {
+			expect(processDate(new Date(2020, 6, 1, 0, 0, 0, 0))).toBe(
+				"2020-07-01T00:00:00Z",
+			);
+		});
 	});
 });