diff --git a/lib/__tests__/storage.test.ts b/lib/__tests__/storage.test.ts
new file mode 100644
index 0000000..700554b
--- /dev/null
+++ b/lib/__tests__/storage.test.ts
@@ -0,0 +1,111 @@
+import {
+  saveContract,
+  deleteContract,
+  getContracts,
+  saveAlert,
+  getAlerts,
+  deleteAlert,
+} from '../storage';
+
+const localStorageMock = (() => {
+  let store: Record<string, string> = {};
+  return {
+    getItem:   (key: string) => store[key] ?? null,
+    setItem:   (key: string, value: string) => { store[key] = value; },
+    removeItem:(key: string) => { delete store[key]; },
+    clear:     () => { store = {}; },
+  };
+})();
+
+Object.defineProperty(global, 'localStorage', { value: localStorageMock });
+
+const contract1 = { id: 'c1', address: 'GABC...001', label: 'Contract Alpha', network: 'mainnet' };
+const contract2 = { id: 'c2', address: 'GDEF...002', label: 'Contract Beta',  network: 'testnet' };
+
+const alert1 = { id: 'a1', contractId: 'c1', type: 'transfer', threshold: 100 };
+const alert2 = { id: 'a2', contractId: 'c1', type: 'invocation', threshold: 0 };
+const alert3 = { id: 'a3', contractId: 'c1', type: 'balance',   threshold: 500 };
+
+beforeEach(() => localStorageMock.clear());
+
+describe('saveContract / getContracts', () => {
+  it('saves a contract and retrieves it', () => {
+    saveContract(contract1);
+    const contracts = getContracts();
+    expect(contracts).toHaveLength(1);
+    expect(contracts[0].id).toBe('c1');
+  });
+
+  it('retrieves multiple saved contracts', () => {
+    saveContract(contract1);
+    saveContract(contract2);
+    expect(getContracts()).toHaveLength(2);
+  });
+
+  it('returns empty array when no contracts saved (empty fallback)', () => {
+    expect(getContracts()).toEqual([]);
+  });
+});
+
+describe('deleteContract', () => {
+  it('removes the correct contract by id', () => {
+    saveContract(contract1);
+    saveContract(contract2);
+    deleteContract('c1');
+    const remaining = getContracts();
+    expect(remaining).toHaveLength(1);
+    expect(remaining[0].id).toBe('c2');
+  });
+
+  it('is a no-op when deleting a non-existent id', () => {
+    saveContract(contract1);
+    deleteContract('does-not-exist');
+    expect(getContracts()).toHaveLength(1);
+  });
+
+  it('results in empty array after deleting the only contract', () => {
+    saveContract(contract1);
+    deleteContract('c1');
+    expect(getContracts()).toEqual([]);
+  });
+});
+
+describe('duplicate contract handling', () => {
+  it('does not create a duplicate when saving the same id twice', () => {
+    saveContract(contract1);
+    saveContract({ ...contract1, label: 'Updated Label' });
+    const contracts = getContracts();
+    expect(contracts).toHaveLength(1);
+  });
+
+  it('updates the existing entry when saving a duplicate id', () => {
+    saveContract(contract1);
+    saveContract({ ...contract1, label: 'Updated Label' });
+    expect(getContracts()[0].label).toBe('Updated Label');
+  });
+});
+
+describe('saveAlert / getAlerts — insertion order', () => {
+  it('returns alerts in insertion order', () => {
+    saveAlert(alert1);
+    saveAlert(alert2);
+    saveAlert(alert3);
+    const alerts = getAlerts('c1');
+    expect(alerts.map(a => a.id)).toEqual(['a1', 'a2', 'a3']);
+  });
+
+  it('returns empty array when no alerts exist for a contract (empty fallback)', () => {
+    expect(getAlerts('no-such-contract')).toEqual([]);
+  });
+});
+
+describe('deleteAlert', () => {
+  it('removes only the specified alert', () => {
+    saveAlert(alert1);
+    saveAlert(alert2);
+    deleteAlert('a1');
+    const alerts = getAlerts('c1');
+    expect(alerts).toHaveLength(1);
+    expect(alerts[0].id).toBe('a2');
+  });
+});