feat: add team cash flow amount presentation

myteamwallet_frontend_modern/src/app/models/transaction-amount.spec.ts

@@ -1,4 +1,50 @@
-import { signedTransactionAmount } from './transaction-amount';
+import { presentCashFlow, signedTransactionAmount } from './transaction-amount';
+
+describe('presentCashFlow', () => {
+  it.each([
+    {
+      amount: 12,
+      type: 0,
+      context: 'player' as const,
+      expected: { direction: 'inflow', amount: 12, sign: '+' },
+    },
+    {
+      amount: -12,
+      type: 'payment',
+      context: 'player' as const,
+      expected: { direction: 'outflow', amount: 12, sign: '−' },
+    },
+    {
+      amount: 8.5,
+      type: { id: 1, name: 'credit' },
+      context: 'team' as const,
+      expected: { direction: 'inflow', amount: 8.5, sign: '+' },
+    },
+    {
+      amount: 8.5,
+      type: { id: 14, name: 'expense' },
+      context: 'team' as const,
+      expected: { direction: 'outflow', amount: 8.5, sign: '−' },
+    },
+    {
+      amount: 7,
+      type: 'fine',
+      context: 'player' as const,
+      expected: { direction: 'neutral', amount: 7, sign: '' },
+    },
+    {
+      amount: -7,
+      type: 'unknown',
+      context: 'player' as const,
+      expected: { direction: 'neutral', amount: 7, sign: '' },
+    },
+  ])(
+    'presents $context $type transactions with their cash-flow direction',
+    ({ amount, type, context, expected }) => {
+      expect(presentCashFlow(amount, type, context)).toEqual(expected);
+    },
+  );
+});
 
 describe('signedTransactionAmount', () => {
   it('shows debit transaction types as negative amounts', () => {