diff --git a/tests/unit/errorHandler.test.ts b/tests/unit/errorHandler.test.ts
deleted file mode 100644
index 8960357..0000000
--- a/tests/unit/errorHandler.test.ts
+++ /dev/null
@@ -1,109 +0,0 @@
-import { AppError } from "$lib/error.types";
-import { createError, formatError, logError } from "$lib/utils/errorUtils";
-import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
-
-describe("errorHandler", () => {
-  let consoleErrorSpy: any;
-
-  beforeEach(() => {
-    consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
-  });
-
-  afterEach(() => {
-    consoleErrorSpy.mockClear();
-    vi.restoreAllMocks();
-  });
-
-  describe("formatError", () => {
-    it("should handle AppError", () => {
-      const error = new AppError("Test error", "TEST_ERROR", true);
-      const result = formatError(error);
-
-      expect(result).toBe("Произошла ошибка: Test error");
-    });
-
-    it("should handle standard Error objects", () => {
-      const error = new Error("Standard error message");
-      const result = formatError(error, "Custom prefix");
-
-      expect(result).toBe("Custom prefix: Standard error message");
-    });
-
-    it("should handle string errors", () => {
-      const result = formatError("String error", "Custom prefix");
-
-      expect(result).toBe("Custom prefix: String error");
-    });
-
-    it("should handle unknown error types", () => {
-      const result = formatError({ some: "object" }, "Custom prefix");
-
-      expect(result).toBe("Custom prefix: Произошла неизвестная ошибка");
-    });
-
-    it("should use default message when none provided", () => {
-      const result = formatError({ some: "object" });
-
-      expect(result).toBe("Произошла ошибка: Произошла неизвестная ошибка");
-    });
-  });
-
-  describe("createError", () => {
-    it("should create AppError with default recoverable flag", () => {
-      const error = createError("Test message", "TEST_CODE");
-
-      expect(error).toBeInstanceOf(AppError);
-      expect(error.message).toBe("Test message");
-      expect(error.code).toBe("TEST_CODE");
-    });
-
-    it("should create AppError with details", () => {
-      const details = { some: "additional info" };
-      const error = createError("Test message", "TEST_CODE", details);
-
-      expect(error.details).toBe(details);
-    });
-  });
-
-  describe("logError", () => {
-    it("should log error with context", () => {
-      const error = new Error("Test error");
-      const context = "Test context";
-
-      logError(error, context);
-
-      expect(consoleErrorSpy).toHaveBeenCalledWith("Error occurred:", {
-        error,
-        context,
-        timestamp: expect.any(String),
-        stack: error.stack,
-      });
-    });
-
-    it("should log error without context", () => {
-      const error = new Error("Test error");
-
-      logError(error);
-
-      expect(consoleErrorSpy).toHaveBeenCalledWith("Error occurred:", {
-        error,
-        context: undefined,
-        timestamp: expect.any(String),
-        stack: error.stack,
-      });
-    });
-
-    it("should handle non-Error objects", () => {
-      const error = "String error";
-
-      logError(error, "Test context");
-
-      expect(consoleErrorSpy).toHaveBeenCalledWith("Error occurred:", {
-        error,
-        context: "Test context",
-        timestamp: expect.any(String),
-        stack: undefined,
-      });
-    });
-  });
-});
diff --git a/tests/unit/errorTypes.test.ts b/tests/unit/errorTypes.test.ts
new file mode 100644
index 0000000..2be963e
--- /dev/null
+++ b/tests/unit/errorTypes.test.ts
@@ -0,0 +1,207 @@
+import { AppError, ImageError, TextError, CanvasError, StorageError } from "$lib/error.types";
+import { describe, expect, it } from "vitest";
+
+describe("error.types", () => {
+  describe("AppError", () => {
+    it("should create AppError with message and code", () => {
+      const error = new AppError("Test error message", "TEST_CODE");
+
+      expect(error).toBeInstanceOf(Error);
+      expect(error).toBeInstanceOf(AppError);
+      expect(error.name).toBe("AppError");
+      expect(error.message).toBe("Test error message");
+      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 = new AppError("Test error message", "TEST_CODE", details);
+
+      expect(error.details).toEqual(details);
+      expect(error.message).toBe("Test error message");
+      expect(error.code).toBe("TEST_CODE");
+    });
+
+    it("should have stack trace", () => {
+      const error = new AppError("Test error", "TEST_CODE");
+
+      expect(error.stack).toBeDefined();
+      expect(typeof error.stack).toBe("string");
+    });
+
+    it("should be throwable and catchable", () => {
+      expect(() => {
+        throw new AppError("Test error", "TEST_CODE");
+      }).toThrow(AppError);
+    });
+
+    it("should be catchable as Error", () => {
+      expect(() => {
+        throw new AppError("Test error", "TEST_CODE");
+      }).toThrow(Error);
+    });
+  });
+
+  describe("ImageError", () => {
+    it("should create ImageError with message", () => {
+      const error = new ImageError("Image loading failed");
+
+      expect(error).toBeInstanceOf(Error);
+      expect(error).toBeInstanceOf(AppError);
+      expect(error).toBeInstanceOf(ImageError);
+      expect(error.name).toBe("AppError");
+      expect(error.message).toBe("Image loading failed");
+      expect(error.code).toBe("IMAGE_ERROR");
+    });
+
+    it("should have correct error code", () => {
+      const error = new ImageError("Test");
+
+      expect(error.code).toBe("IMAGE_ERROR");
+    });
+
+    it("should be identifiable as ImageError", () => {
+      const error = new ImageError("Test");
+
+      expect(error instanceof ImageError).toBe(true);
+    });
+  });
+
+  describe("TextError", () => {
+    it("should create TextError with message", () => {
+      const error = new TextError("Text validation failed");
+
+      expect(error).toBeInstanceOf(Error);
+      expect(error).toBeInstanceOf(AppError);
+      expect(error).toBeInstanceOf(TextError);
+      expect(error.name).toBe("AppError");
+      expect(error.message).toBe("Text validation failed");
+      expect(error.code).toBe("TEXT_ERROR");
+    });
+
+    it("should have correct error code", () => {
+      const error = new TextError("Test");
+
+      expect(error.code).toBe("TEXT_ERROR");
+    });
+
+    it("should be identifiable as TextError", () => {
+      const error = new TextError("Test");
+
+      expect(error instanceof TextError).toBe(true);
+    });
+  });
+
+  describe("CanvasError", () => {
+    it("should create CanvasError with message", () => {
+      const error = new CanvasError("Canvas rendering failed");
+
+      expect(error).toBeInstanceOf(Error);
+      expect(error).toBeInstanceOf(AppError);
+      expect(error).toBeInstanceOf(CanvasError);
+      expect(error.name).toBe("AppError");
+      expect(error.message).toBe("Canvas rendering failed");
+      expect(error.code).toBe("CANVAS_ERROR");
+    });
+
+    it("should have correct error code", () => {
+      const error = new CanvasError("Test");
+
+      expect(error.code).toBe("CANVAS_ERROR");
+    });
+
+    it("should be identifiable as CanvasError", () => {
+      const error = new CanvasError("Test");
+
+      expect(error instanceof CanvasError).toBe(true);
+    });
+  });
+
+  describe("StorageError", () => {
+    it("should create StorageError with message", () => {
+      const error = new StorageError("Storage operation failed");
+
+      expect(error).toBeInstanceOf(Error);
+      expect(error).toBeInstanceOf(AppError);
+      expect(error).toBeInstanceOf(StorageError);
+      expect(error.name).toBe("AppError");
+      expect(error.message).toBe("Storage operation failed");
+      expect(error.code).toBe("STORAGE_ERROR");
+    });
+
+    it("should have correct error code", () => {
+      const error = new StorageError("Test");
+
+      expect(error.code).toBe("STORAGE_ERROR");
+    });
+
+    it("should be identifiable as StorageError", () => {
+      const error = new StorageError("Test");
+
+      expect(error instanceof StorageError).toBe(true);
+    });
+  });
+
+  describe("ErrorType union", () => {
+    it("should accept all error types", () => {
+      const errors: Array<AppError | ImageError | TextError | CanvasError | StorageError> = [
+        new AppError("Test", "TEST"),
+        new ImageError("Test"),
+        new TextError("Test"),
+        new CanvasError("Test"),
+        new StorageError("Test"),
+      ];
+
+      errors.forEach(error => {
+        expect(error).toBeInstanceOf(AppError);
+        expect(error).toBeInstanceOf(Error);
+      });
+    });
+
+    it("should allow type narrowing with instanceof", () => {
+      const errors: Array<AppError | ImageError | TextError | CanvasError | StorageError> = [
+        new ImageError("Test"),
+        new TextError("Test"),
+      ];
+
+      const imageErrors = errors.filter(e => e instanceof ImageError);
+      const textErrors = errors.filter(e => e instanceof TextError);
+
+      expect(imageErrors).toHaveLength(1);
+      expect(textErrors).toHaveLength(1);
+    });
+  });
+
+  describe("Error handling patterns", () => {
+    it("should handle errors in try-catch blocks", () => {
+      let caughtError: AppError | null = null;
+
+      try {
+        throw new ImageError("Image failed to load");
+      } catch (error) {
+        if (error instanceof AppError) {
+          caughtError = error;
+        }
+      }
+
+      expect(caughtError).not.toBeNull();
+      expect(caughtError?.code).toBe("IMAGE_ERROR");
+    });
+
+    it("should preserve error details through error handling", () => {
+      const originalError = new AppError("Test", "TEST", { id: 123 });
+      let caughtError: AppError | null = null;
+
+      try {
+        throw originalError;
+      } catch (error) {
+        if (error instanceof AppError) {
+          caughtError = error;
+        }
+      }
+
+      expect(caughtError?.details).toEqual({ id: 123 });
+    });
+  });
+});