diff --git a/__tests__/utils/filesystem.spec.ts b/__tests__/utils/filesystem.spec.ts
new file mode 100644
index 00000000..a920567d
--- /dev/null
+++ b/__tests__/utils/filesystem.spec.ts
@@ -0,0 +1,59 @@
+import { beforeAll, describe, expect, test } from 'vitest'
+import { isFileSystemDirectoryEntry, isFileSystemEntry, isFileSystemFileEntry } from '../../lib/utils/filesystem'
+
+describe('File and Directory API helpers', () => {
+	describe('Without browser support', () => {
+		beforeAll(() => {
+			// @ts-expect-error This is not optional, but we need this removed for testing
+			delete window.FileSystemEntry
+			// @ts-expect-error This is not optional, but we need this removed for testing
+			delete window.FileSystemFileEntry
+			// @ts-expect-error This is not optional, but we need this removed for testing
+			delete window.FileSystemDirectoryEntry
+		})
+
+		test('isFileSystemDirectoryEntry', () => {
+			expect(isFileSystemDirectoryEntry({ })).toBe(false)
+		})
+		test('isFileSystemFileEntry', () => {
+			expect(isFileSystemFileEntry({ })).toBe(false)
+		})
+		test('isFileSystemEntry', () => {
+			expect(isFileSystemEntry({ })).toBe(false)
+		})
+	})
+
+	describe('With browser support', () => {
+		beforeAll(() => {
+			// @ts-expect-error Mocking the class - as of today (2024) neither jsdom nor happy-dom support this
+			window.FileSystemEntry = class A {}
+			// @ts-expect-error Mocking the class - as of today (2024) neither jsdom nor happy-dom support this
+			window.FileSystemFileEntry = class B extends window.FileSystemEntry {}
+			// @ts-expect-error Mocking the class - as of today (2024) neither jsdom nor happy-dom support this
+			window.FileSystemDirectoryEntry = class C extends window.FileSystemEntry {}
+		})
+
+		test('isFileSystemDirectoryEntry with other object', () => {
+			expect(isFileSystemDirectoryEntry({ })).toBe(false)
+		})
+		test('isFileSystemFileEntry with other object', () => {
+			expect(isFileSystemFileEntry({ })).toBe(false)
+		})
+		test('isFileSystemEntry with other object', () => {
+			expect(isFileSystemEntry({ })).toBe(false)
+		})
+
+		test('isFileSystemDirectoryEntry with real entry', () => {
+			const object = new window.FileSystemDirectoryEntry()
+			expect(isFileSystemDirectoryEntry(object)).toBe(true)
+		})
+		test('isFileSystemFileEntry with real entry', () => {
+			const object = new window.FileSystemFileEntry()
+			expect(isFileSystemFileEntry(object)).toBe(true)
+		})
+		test('isFileSystemEntry with real entry', () => {
+			const object = new window.FileSystemEntry()
+			expect(isFileSystemEntry(object)).toBe(true)
+		})
+	})
+})
diff --git a/lib/utils/filesystem.ts b/lib/utils/filesystem.ts
index 8e82a80d..e600fa7e 100644
--- a/lib/utils/filesystem.ts
+++ b/lib/utils/filesystem.ts
@@ -3,6 +3,6 @@
 // Helper to support browser that do not support the API
 export const isFileSystemDirectoryEntry = (o: unknown): o is FileSystemDirectoryEntry => 'FileSystemDirectoryEntry' in window && o instanceof FileSystemDirectoryEntry
 
-export const isFileSystemFileEntry = (o: unknown): o is FileSystemFileEntry => 'FilesystemFileEntry' in window && o instanceof FileSystemFileEntry
+export const isFileSystemFileEntry = (o: unknown): o is FileSystemFileEntry => 'FileSystemFileEntry' in window && o instanceof FileSystemFileEntry
 
 export const isFileSystemEntry = (o: unknown): o is FileSystemEntry => 'FileSystemEntry' in window && o instanceof FileSystemEntry