#85 [Error Handling] connectAccount leaves wallet in partially-conn…

src/__tests__/stellarBalance.test.ts

@@ -0,0 +1,106 @@
+/**
+ * Tests for the error contract of stellar.getBalance / getTokenBalance.
+ *
+ * The connect flow refuses to mark a wallet as connected when the balance
+ * cannot be verified, so the service must distinguish:
+ *  - unfunded account (NotFoundError) → resolves '0' (valid zero balance)
+ *  - infrastructure/network failure    → rejects (cannot verify balance)
+ */
+
+import './__mocks__/rn-modules';
+import { Horizon, NotFoundError } from '@stellar/stellar-sdk';
+import { getBalance, getTokenBalance } from '../services/stellar';
+
+type LoadAccount = Horizon.Server['loadAccount'];
+
+const loadAccountSpy = jest.spyOn(
+  Horizon.Server.prototype,
+  'loadAccount',
+) as jest.MockedFunction<LoadAccount>;
+
+function accountRecord(balances: Record<string, string>[]) {
+  return { balances } as never;
+}
+
+function notFound(): never {
+  return new NotFoundError(
+    'Account not found',
+    new Response(null, { status: 404 }),
+  ) as never;
+}
+
+beforeEach(() => {
+  loadAccountSpy.mockReset();
+});
+
+afterAll(() => {
+  loadAccountSpy.mockRestore();
+});
+
+describe('getBalance', () => {
+  it('returns the native XLM balance for a funded account', async () => {
+    loadAccountSpy.mockResolvedValue(
+      accountRecord([{ asset_type: 'native', balance: '42.5' }]),
+    );
+    await expect(getBalance('GCFUNDED')).resolves.toBe('42.5');
+  });
+
+  it("returns '0' when the account holds no native balance entry", async () => {
+    loadAccountSpy.mockResolvedValue(accountRecord([]));
+    await expect(getBalance('GCEMPTY')).resolves.toBe('0');
+  });
+
+  it("resolves '0' for an unfunded account (NotFoundError)", async () => {
+    loadAccountSpy.mockRejectedValue(notFound());
+    await expect(getBalance('GCUNFUNDED')).resolves.toBe('0');
+  });
+
+  it('rejects on network failure so the connect flow can roll back', async () => {
+    const networkError = new Error('Network request failed');
+    loadAccountSpy.mockRejectedValue(networkError);
+    await expect(getBalance('GCOFFLINE')).rejects.toBe(networkError);
+  });
+});
+
+describe('getTokenBalance', () => {
+  it('returns the trustlined asset balance when it exists', async () => {
+    loadAccountSpy.mockResolvedValue(
+      accountRecord([
+        { asset_type: 'native', balance: '1' },
+        {
+          asset_type: 'credit_alphanum4',
+          asset_code: 'ECO',
+          asset_issuer: 'TESTISSUER',
+          balance: '75',
+        },
+      ]),
+    );
+    await expect(
+      getTokenBalance('GCFUNDED', 'ECO', 'TESTISSUER'),
+    ).resolves.toBe('75');
+  });
+
+  it("returns '0' when the account has no trustline for the asset", async () => {
+    loadAccountSpy.mockResolvedValue(
+      accountRecord([{ asset_type: 'native', balance: '1' }]),
+    );
+    await expect(
+      getTokenBalance('GCFUNDED', 'ECO', 'TESTISSUER'),
+    ).resolves.toBe('0');
+  });
+
+  it("resolves '0' for an unfunded account (NotFoundError)", async () => {
+    loadAccountSpy.mockRejectedValue(notFound());
+    await expect(
+      getTokenBalance('GCUNFUNDED', 'ECO', 'TESTISSUER'),
+    ).resolves.toBe('0');
+  });
+
+  it('rejects on network failure so the connect flow can roll back', async () => {
+    const networkError = new Error('Horizon unavailable');
+    loadAccountSpy.mockRejectedValue(networkError);
+    await expect(
+      getTokenBalance('GCOFFLINE', 'ECO', 'TESTISSUER'),
+    ).rejects.toBe(networkError);
+  });
+});