public void TransactionExists_tells_if_an_id_exists(int testId, bool expectedResult)
        {
            // Arrange
            var transactions = new List <Transaction> {
                new Transaction {
                    ID = 1
                }
            }.AsQueryable();

            _mockRepo.Setup(m => m.GetTransactions(It.IsAny <bool>(), It.IsAny <bool>())).Returns(transactions);

            // Act
            var result = _testService.TransactionExists(testId);

            // Assert
            Assert.AreEqual(expectedResult, result);
        }