diff --git a/src/entities/Font/model/store/unifiedFontStore/unifiedFontStore.test.ts b/src/entities/Font/model/store/unifiedFontStore/unifiedFontStore.test.ts
new file mode 100644
index 0000000..44e2200
--- /dev/null
+++ b/src/entities/Font/model/store/unifiedFontStore/unifiedFontStore.test.ts
@@ -0,0 +1,85 @@
+import { QueryClient } from '@tanstack/query-core';
+import {
+    afterEach,
+    beforeEach,
+    describe,
+    expect,
+    it,
+    vi,
+} from 'vitest';
+import {
+    FontNetworkError,
+    FontResponseError,
+} from '../../../lib/errors/errors';
+
+vi.mock('$shared/api/queryClient', () => ({
+    queryClient: new QueryClient({
+        defaultOptions: {
+            queries: {
+                retry: 0,
+                gcTime: 0,
+            },
+        },
+    }),
+}));
+
+vi.mock('../../../api', () => ({
+    fetchProxyFonts: vi.fn(),
+}));
+
+import { queryClient } from '$shared/api/queryClient';
+import { fetchProxyFonts } from '../../../api';
+import { UnifiedFontStore } from './unifiedFontStore.svelte';
+
+const mockedFetch = fetchProxyFonts as ReturnType<typeof vi.fn>;
+
+describe('UnifiedFontStore.fetchFn error paths', () => {
+    let store: UnifiedFontStore;
+
+    beforeEach(() => {
+        store = new UnifiedFontStore({ limit: 10 });
+    });
+
+    afterEach(() => {
+        store.destroy();
+        queryClient.clear();
+        vi.resetAllMocks();
+    });
+
+    it('sets isError and error getter when fetchProxyFonts throws', async () => {
+        mockedFetch.mockRejectedValue(new Error('network down'));
+        await store.refetch().catch((e: unknown) => e);
+
+        expect(store.error).toBeInstanceOf(FontNetworkError);
+        expect((store.error as FontNetworkError).cause).toBeInstanceOf(Error);
+        expect(store.isError).toBe(true);
+    });
+
+    it('throws FontResponseError when response is falsy', async () => {
+        mockedFetch.mockResolvedValue(undefined);
+
+        await store.refetch().catch((e: unknown) => e);
+
+        expect(store.error).toBeInstanceOf(FontResponseError);
+        expect((store.error as FontResponseError).field).toBe('response');
+    });
+
+    it('throws FontResponseError when response.fonts is missing', async () => {
+        mockedFetch.mockResolvedValue({ total: 0, limit: 10, offset: 0 });
+
+        await store.refetch().catch((e: unknown) => e);
+
+        expect(store.error).toBeInstanceOf(FontResponseError);
+        expect((store.error as FontResponseError).field).toBe('response.fonts');
+    });
+
+    it('throws FontResponseError when response.fonts is not an array', async () => {
+        mockedFetch.mockResolvedValue({ fonts: 'bad', total: 0, limit: 10, offset: 0 });
+
+        await store.refetch().catch((e: unknown) => e);
+
+        expect(store.error).toBeInstanceOf(FontResponseError);
+        expect((store.error as FontResponseError).field).toBe('response.fonts');
+        expect((store.error as FontResponseError).received).toBe('bad');
+    });
+});