fix: count brokerage cash once and skip short-position return percent (WealthLedger/backend#140)

src/modules/investments/brokerage-accounts/brokerage-accounts.service.spec.ts

@@ -128,6 +128,27 @@ describe('saved brokerage account projection', () => {
     });
   });
 
+  it('omits return percent for a currency with short positions', async () => {
+    portfolio.saved.mockResolvedValueOnce({
+      membership: meta,
+      accounts: [{
+        id: 'a', name: 'A', type: 'BROKERAGE', openedOn: null, meta,
+        snapshot: {
+          cashBalances: [], structure: {}, totalsByCurrency: [],
+          positions: [
+            { type: 'STOCK', quantity: '-2', averagePurchasePrice: { currency: 'RUB', value: '100' }, absoluteReturn: { currency: 'RUB', value: '-20' } },
+            { type: 'STOCK', quantity: '1', averagePurchasePrice: { currency: 'USD', value: '10' }, absoluteReturn: { currency: 'USD', value: '1' } },
+          ],
+        },
+      }],
+    });
+
+    expect((await service.list('owner')).data?.[0]?.portfolioSummary?.unrealizedReturnByCurrency).toEqual([
+      { currency: 'RUB', absolute: '-20', costBasis: '-200', percent: null, partial: false },
+      { currency: 'USD', absolute: '1', costBasis: '10', percent: '10', partial: false },
+    ]);
+  });
+
   it('observes the latest hourly walk without starting another one', async () => {
     portfolio.saved.mockResolvedValue({ membership: meta, accounts: [] });
     sync.hourly.mockResolvedValue({