public void Constructor()
        {
            var expenseService = new Mock <IExpenseService>();
            var actual         = new ReferExpense(expenseService.Object);

            Assert.NotNull(actual.Expenses);
            Assert.Equal(0, actual.Expenses.Count);
        }
        public async Task SearchAsync()
        {
            var expenseService = new Mock <IExpenseService>();
            var expense        = new Expense();
            var expenses       = new[] { expense };

            expenseService
            .Setup(m => m.GetExpensesAsync())
            .ReturnsAsync(expenses);

            var actual = new ReferExpense(expenseService.Object);
            await actual.SearchAsync();

            Assert.NotNull(actual.Expenses);
            Assert.Equal(1, actual.Expenses.Count);
            Assert.Equal(expense, actual.Expenses[0]);
        }