public async Task AddTransactionTypeAsync_Returns_New_TransactionType()
{
//Arrange
var service = new TransactionTypeService(_myRestaurantContext);
//Act
var result = await service.AddTransactionTypeAsync(new TransactionType { Type = "Salary" });
//Assert
result.Should().BeAssignableTo <TransactionType>();
result.Type.Should().Be("Salary");
//Act
var transactionTypes = await service.GetTransactionTypesAsync();
//Assert
transactionTypes.Should().HaveCount(18);
}