diff --git a/svelte.config.js b/svelte.config.js
index 20342dd..4b5b7c4 100644
--- a/svelte.config.js
+++ b/svelte.config.js
@@ -14,6 +14,7 @@ const config = {
     },
     alias: {
       $components: "src/components",
+      $routes: "src/routes",
       $stores: "src/stores",
       $states: "src/states",
       $services: "src/services",
diff --git a/tests/setup.ts b/tests/setup.ts
index e69de29..407f804 100644
--- a/tests/setup.ts
+++ b/tests/setup.ts
@@ -0,0 +1 @@
+import "@testing-library/jest-dom/vitest";
diff --git a/tests/unit/errorUtils.test.ts b/tests/unit/errorUtils.test.ts
new file mode 100644
index 0000000..16f5fff
--- /dev/null
+++ b/tests/unit/errorUtils.test.ts
@@ -0,0 +1,155 @@
+import { AppError, ImageError, TextError, CanvasError, StorageError } from "$lib/error.types";
+import { formatError, createError, logError } from "$lib/utils/errorUtils";
+import { describe, expect, it, vi } from "vitest";
+
+describe("errorUtils", () => {
+  describe("formatError", () => {
+    it("should format AppError", () => {
+      const error = new AppError("Test error", "TEST_CODE");
+      const result = formatError(error, "Default message");
+
+      expect(result).toBe("Default message: Test error");
+    });
+
+    it("should format Error", () => {
+      const error = new Error("Test error");
+      const result = formatError(error, "Default message");
+
+      expect(result).toBe("Default message: Test error");
+    });
+
+    it("should format string error", () => {
+      const error = "String error message";
+      const result = formatError(error, "Default message");
+
+      expect(result).toBe("Default message: String error message");
+    });
+
+    it("should format unknown error", () => {
+      const error = { custom: "object" };
+      const result = formatError(error, "Default message");
+
+      expect(result).toBe("Default message: Произошла неизвестная ошибка");
+    });
+
+    it("should use default message when not provided", () => {
+      const error = new Error("Test error");
+      const result = formatError(error);
+
+      expect(result).toBe("Произошла ошибка: Test error");
+    });
+
+    it("should format ImageError", () => {
+      const error = new ImageError("Image failed");
+      const result = formatError(error, "Default message");
+
+      expect(result).toBe("Default message: Image failed");
+    });
+
+    it("should format TextError", () => {
+      const error = new TextError("Text failed");
+      const result = formatError(error, "Default message");
+
+      expect(result).toBe("Default message: Text failed");
+    });
+
+    it("should format CanvasError", () => {
+      const error = new CanvasError("Canvas failed");
+      const result = formatError(error, "Default message");
+
+      expect(result).toBe("Default message: Canvas failed");
+    });
+
+    it("should format StorageError", () => {
+      const error = new StorageError("Storage failed");
+      const result = formatError(error, "Default message");
+
+      expect(result).toBe("Default message: Storage failed");
+    });
+  });
+
+  describe("createError", () => {
+    it("should create AppError with message and code", () => {
+      const error = createError("Test error", "TEST_CODE");
+
+      expect(error).toBeInstanceOf(AppError);
+      expect(error.message).toBe("Test error");
+      expect(error.code).toBe("TEST_CODE");
+      expect(error.details).toBeUndefined();
+    });
+
+    it("should create AppError with message, code and details", () => {
+      const details = { userId: 123, action: "test" };
+      const error = createError("Test error", "TEST_CODE", details);
+
+      expect(error.details).toEqual(details);
+      expect(error.message).toBe("Test error");
+      expect(error.code).toBe("TEST_CODE");
+    });
+  });
+
+  describe("logError", () => {
+    it("should log Error with stack", () => {
+      const consoleSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+      const error = new Error("Test error");
+
+      logError(error, "Test context");
+
+      expect(consoleSpy).toHaveBeenCalledWith("Error occurred:", {
+        error,
+        context: "Test context",
+        timestamp: expect.any(String),
+        stack: expect.any(String),
+      });
+
+      consoleSpy.mockRestore();
+    });
+
+    it("should log AppError with stack", () => {
+      const consoleSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+      const error = new AppError("Test error", "TEST_CODE");
+
+      logError(error, "Test context");
+
+      expect(consoleSpy).toHaveBeenCalledWith("Error occurred:", {
+        error,
+        context: "Test context",
+        timestamp: expect.any(String),
+        stack: expect.any(String),
+      });
+
+      consoleSpy.mockRestore();
+    });
+
+    it("should log string error without stack", () => {
+      const consoleSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+
+      logError("String error", "Test context");
+
+      expect(consoleSpy).toHaveBeenCalledWith("Error occurred:", {
+        error: "String error",
+        context: "Test context",
+        timestamp: expect.any(String),
+        stack: undefined,
+      });
+
+      consoleSpy.mockRestore();
+    });
+
+    it("should log error without context", () => {
+      const consoleSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+      const error = new Error("Test error");
+
+      logError(error);
+
+      expect(consoleSpy).toHaveBeenCalledWith("Error occurred:", {
+        error,
+        context: undefined,
+        timestamp: expect.any(String),
+        stack: expect.any(String),
+      });
+
+      consoleSpy.mockRestore();
+    });
+  });
+});
diff --git a/tests/unit/routes/layout.settings.test.ts b/tests/unit/routes/layout.settings.test.ts
new file mode 100644
index 0000000..786bb55
--- /dev/null
+++ b/tests/unit/routes/layout.settings.test.ts
@@ -0,0 +1,12 @@
+import { prerender, ssr } from "$routes/+layout";
+import { describe, expect, it } from "vitest";
+
+describe("+layout.ts", () => {
+  it("should export ssr as false", () => {
+    expect(ssr).toBe(false);
+  });
+
+  it("should export prerender as true", () => {
+    expect(prerender).toBe(true);
+  });
+});
diff --git a/tests/unit/routes/layout.test.ts b/tests/unit/routes/layout.test.ts
new file mode 100644
index 0000000..ec33e11
--- /dev/null
+++ b/tests/unit/routes/layout.test.ts
@@ -0,0 +1,50 @@
+import { themeState } from "$states/theme.svelte";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+describe("+layout.svelte", () => {
+  beforeEach(() => {
+    themeState.theme = "dark";
+    vi.clearAllMocks();
+  });
+
+  it("should apply dark theme", () => {
+    themeState.theme = "dark";
+
+    expect(themeState.theme).toBe("dark");
+  });
+
+  it("should apply light theme", () => {
+    themeState.theme = "light";
+
+    expect(themeState.theme).toBe("light");
+  });
+
+  it("should toggle theme", () => {
+    themeState.theme = "dark";
+    themeState.toggle();
+
+    expect(themeState.theme).toBe("light");
+  });
+});
+
+import Layout from "$routes/+layout.svelte";
+import { render, screen } from "@testing-library/svelte";
+import { createRawSnippet } from "svelte";
+
+describe("Layout Component Coverage", () => {
+  it("should render children snippet and initialize props", () => {
+    const testId = "test-child";
+    const childrenSnippet = createRawSnippet(() => ({
+      render: () => `<span data-testid="${testId}">Hello</span>`,
+    }));
+
+    render(Layout, {
+      props: {
+        children: childrenSnippet,
+      },
+    });
+
+    expect(screen.getByTestId(testId)).toBeInTheDocument();
+    expect(screen.getByRole("banner")).toBeInTheDocument();
+  });
+});
diff --git a/tests/unit/services/downloadService.test.ts b/tests/unit/services/downloadService.test.ts
index 51d72be..0de60f1 100644
--- a/tests/unit/services/downloadService.test.ts
+++ b/tests/unit/services/downloadService.test.ts
@@ -10,13 +10,11 @@ vi.mock("file-saver", () => {
 });
 
 vi.mock("jszip", () => {
-  // Создаем объект с методами заранее, чтобы иметь к ним доступ
   const mockZipInstance = {
     file: vi.fn().mockReturnThis(),
     generateAsync: vi.fn().mockResolvedValue(new Blob([])),
   };
 
-  // Возвращаем функцию-конструктор
   return {
     default: vi.fn(function () {
       return mockZipInstance;
diff --git a/tests/unit/states/konvaAllStages.test.ts b/tests/unit/states/konvaAllStages.test.ts
index 1d46446..b7e72f4 100644
--- a/tests/unit/states/konvaAllStages.test.ts
+++ b/tests/unit/states/konvaAllStages.test.ts
@@ -3,7 +3,6 @@ import { konvaAllStagesState } from "$states/konvaAllStages.svelte";
 
 describe("konvaAllStages.svelte", () => {
   beforeEach(() => {
-    // Clear the array before each test
     konvaAllStagesState.length = 0;
   });