feat: added one integration test (closes #19)

src/transaction/transaction.controller.spec.ts

@@ -173,4 +173,17 @@ describe('TransactionController Unit Tests', () => {
 
     expect(result).to.eql('{"amount":"4.17","currency":"EUR"}');
   });
+
+  it('returns correct amount for small transactions', async () => {
+    const mockTransactionInput: TransactionInput = {
+      date: '2021-01-05',
+      amount: '0.01',
+      currency: 'EUR',
+      client_id: 1,
+    };
+
+    const result = await transactionController.commission(mockTransactionInput);
+
+    expect(result).to.eql('{"amount":"0.05","currency":"EUR"}');
+  });
 });