I am overriding SaveChangesAsync to handle DbUpdateConcurrencyException. For example:
public override async Task<int> SaveChangesAsync(CancellationToken cancellationToken = default)
{
var saved = false;
var loopCount = 0;
var count = 0;
while (!saved && ++loopCount < 4)
{
try
{
count = await base.SaveChangesAsync(cancellationToken).ConfigureAwait(false);
saved = true;
}
catch (DbUpdateConcurrencyException ex)
{
foreach (var entry in ex.Entries)
{
entry.OriginalValues.SetValues(entry.CurrentValues);
}
}
}
return count;
}
My question is: how do I force the base class (DbContext) to throw a DbUpdateConcurrencyException in a test?
Note: Please don't suggest wrapping or other abstractions as those are certainly overkill in this case.
If a dbcontext is waited on using should one still use SaveChangesAsync() or SaveChanges() should be enough?
await using var dbContxt = new dbContxt(con);
public async Task<bool> SaveData(strig con, object data)
{
await using var dbContxt = new dbContxt(con);
var myData = new MyData
{
a = data.a,
b = data.b,
c = data.c,
};
dbContxt.MyData.Add(myData);
var result = await dbContxt.SaveChangesAsync();
return result > 0;
}
}
I have refactored a Web API to rely on async/await in ASP.NET Core 3.1 and I have the following scenario: a statistics method is sequentially computing a list of indicators which are defined in a list.
readonly Dictionary<StatisticItemEnum, Func<Task<SimpleStatisticItemApiModel>>> simpleItemActionMap =
new Dictionary<StatisticItemEnum, Func<Task<SimpleStatisticItemApiModel>>>();
private void InitSimpleStatisticFunctionsMap()
{
simpleItemActionMap.Add(StatisticItemEnum.AllQuestionCount, GetAllQuestionCountApiModel);
simpleItemActionMap.Add(StatisticItemEnum.AllAnswerCount, GetAllAnswerCountApiModel);
simpleItemActionMap.Add(StatisticItemEnum.AverageAnswer, GetAverageAnswer);
// other mappings here
}
private async Task<SimpleStatisticItemApiModel> GetAllQuestionCountApiModel()
{
// await for database operation
}
private async Task<SimpleStatisticItemApiModel> GetAllAnswerCountApiModel()
{
// await for database operation
}
private async Task<SimpleStatisticItemApiModel> GetAverageAnswer()
{
// await for database operation
}
The code sequentially goes through each item and computes it and after the refactoring it is looking like this:
itemIds.ForEach(itemId =>
{
var itemEnumValue = (StatisticItemEnum) itemId;
if (simpleItemActionMap.ContainsKey(itemEnumValue))
{
var result = simpleItemActionMap[itemEnumValue]().Result;
payload.SimpleStatisticItemModels.Add(result);
}
});
I know that Task.Result might lead to deadlocks, but I could not find any other way to make this work.
Question: How to execute a dynamic list of async functions in a sequential way?
You should change the ForEach call to a regular foreach, and then you can use await:
foreach (var itemId in itemIds)
{
var itemEnumValue = (StatisticItemEnum) itemId;
if (simpleItemActionMap.ContainsKey(itemEnumValue))
{
var result = await simpleItemActionMap[itemEnumValue]();
payload.SimpleStatisticItemModels.Add(result);
}
}
Do not make the ForEach lambda async; that will result in an async void method, and you should avoid async void.
I think you can do this:
itemIds.ForEach(async itemId =>
{
var itemEnumValue = (StatisticItemEnum) itemId;
if (simpleItemActionMap.ContainsKey(itemEnumValue))
{
var result = await simpleItemActionMap[itemEnumValue]();
payload.SimpleStatisticItemModels.Add(result);
}
});
I started with ASP.Net Core 2.0, I'm trying to rewrite a method GetAll by search use stored procedure. Here is method search:
public async Task<List<DepartmentTypeDto>> SearchDepartmentType()
{
EnsureConnectionOpen();
using (var command = CreateCommand("CM_DEPT_GROUP_Search", CommandType.StoredProcedure))
{
using (var dataReader = await command.ExecuteReaderAsync())
{
List<DepartmentTypeDto> result = new List<DepartmentTypeDto>();
while (dataReader.Read())
{
DepartmentTypeDto departmentTypeDto = new DepartmentTypeDto
{
GROUP_ID = dataReader["GROUP_ID"].ToString(),
GROUP_CODE = dataReader["GROUP_CODE"].ToString(),
GROUP_NAME = dataReader["GROUP_NAME"].ToString(),
NOTES = dataReader["NOTES"].ToString(),
RECORD_STATUS = dataReader["RECORD_STATUS"].ToString(),
MAKER_ID = dataReader["MAKER_ID"].ToString(),
CREATE_DT = Convert.ToDateTime(dataReader["CREATE_DT"]),
AUTH_STATUS = dataReader["AUTH_STATUS"].ToString(),
CHECKER_ID = dataReader["CHECKER_ID"].ToString(),
APPROVE_DT = Convert.ToDateTime(dataReader["APPROVE_DT"]),
AUTH_STATUS_NAME = dataReader["AUTH_STATUS_NAME"].ToString(),
RECORD_STATUS_NAME = dataReader["RECORD_STATUS_NAME"].ToString()
};
}
return result;
}
}
}
Here is the service:
public async Task<PagedResultDto<GetDepartmentTypeForView>> GetAll(GetAllDepartmentTypesInput input)
{
var filteredDepartmentTypes = _departmentTypeRepository.SearchDepartmentType();
var query = (from o in filteredDepartmentTypes
select new GetDepartmentTypeForView() { DepartmentType = ObjectMapper.Map<DepartmentTypeDto>(o) });
var totalCount = await query.CountAsync();
var departmentTypes = await query
.OrderBy(input.Sorting ?? "departmentType.id asc")
.PageBy(input)
.ToListAsync();
return new PagedResultDto<GetDepartmentTypeForView>(totalCount, departmentTypes);
}
But I get an error:
Task<List<DepartmentTypeDto>> does not contain a definition for Select
Does anyone know what I should do? I work on Asp.Net Zero.
I changed my search method
public IQueryable<DepartmentTypeView> SearchDepartmentType(GetAllDepartmentTypesInput input, int top)
{
try
{
var GROUP_FILTER = input.Filter;
var GROUP_CODE = input.GROUP_CODEFilter;
var GROUP_NAME = input.GROUP_NAMEFilter;
var AUTH_STATUS = input.AUTH_STATUSFilter;
var result = Context.Query<DepartmentTypeView>().FromSql($"EXEC CM_DEPT_GROUP_Search #p_GROUP_FILTER = {GROUP_FILTER}, #p_GROUP_CODE={GROUP_CODE}, #p_GROUP_NAME={GROUP_NAME}, #p_AUTH_STATUS={AUTH_STATUS}, #p_TOP={top}");
return result;
}
catch
{
return null;
}
}
and in the service, I call that function
var filteredDepartmentTypes = _departmentTypeRepository.SearchDepartmentType(input,100);
I also create new class to keep the result and don't forget to map that class with DTO class
configuration.CreateMap<DepartmentTypeView, DepartmentTypeDto>();
It works for me.
I want to automate the Setup code by a given array containing expected result and parameters.
Something like data driven setup.
My existing code:
var mock = new Mock<ILogin>();
var testDataTable = new object[,]
{
{ LoginResult.Success, "Jack", "123!##"}
, { LoginResult.WrongPassword, "Jack", "123321"}
, { LoginResult.NoSuchUser, "Peter", "123!##"}
};
// ForEachRow is my own extension method
testDataTable.ForEachRow((row) =>
{
var result = (LoginResult)row[0];
var username = (string)row[1];
var password = (string)row[2];
mock.Setup(o => o.Login(
It.Is<string>(u => u == username),
It.Is<string>(p => p == password)
)).Returns(result);
});
return mock.Object;
Code that I wish:
var mock = new Mock<ILogin>();
new object[,]
{
{ LoginResult.Success, "Jack", "123!##"}
, { LoginResult.WrongPassword, "Jack", "123321"}
, { LoginResult.NoSuchUser, "Peter", "123!##"}
}.ForEachRow((row) =>
{
var exprTree = (ILogin o)=>o.Login("ANY", "ANY");
AutoSetup(mock, exprTree, row); // <---- How to write this AutoSetup?
});
return mock.Object;
How to write the AutoSetup(mock, exprTree, dataArray) function above?
It takes three parameters:
mock: A mock object, e.g. new Mock()
exprTree: Expression tree that represents a method to be setup
dataArray: An object[], the 0 element is the expected result, and others are parameters that passed to the method
This was an interesting challenge. I think I have a working implementation for your AutoSetup method, using the expressions API. If anyone has a simpler solution, I'd love to see it.
static void AutoSetup<TMock, TResult>(Mock<TMock> mock, Expression<Func<TMock, TResult>> exprTree, object[] items) where TMock : class
{
var methodCallExpr = exprTree.Body as MethodCallExpression;
var arguments = items.Skip(1).Select(o => Expression.Constant(o));
var updatedMethod = methodCallExpr.Update(methodCallExpr.Object, arguments);
var updatedLambda = exprTree.Update(updatedMethod, exprTree.Parameters);
mock.Setup(updatedLambda).Returns((TResult)items[0]);
}
Here is a full working test as a console app, with an implementation of ForEachRow, which you didn't provide.
class Program
{
static void Main(string[] args)
{
var login = SetUp();
Console.WriteLine(login.Login("Jack", "123!##"));
Console.WriteLine(login.Login("Jack", "123321"));
Console.WriteLine(login.Login("Peter", "123!##"));
Console.ReadKey();
}
static ILogin SetUp()
{
var mock = new Mock<ILogin>(MockBehavior.Strict);
var rows = new object[,]
{
{ LoginResult.Success, "Jack", "123!##" },
{ LoginResult.WrongPassword, "Jack", "123321" },
{ LoginResult.NoSuchUser, "Peter", "123!##" }
};
rows.ForEachRow((row) => AutoSetup(mock, (ILogin l) => l.Login("ANY", "ANY"), row));
return mock.Object;
}
private static void AutoSetup<TMock, TResult>(Mock<TMock> mock, Expression<Func<TMock, TResult>> exprTree, object[] items) where TMock : class
{
var methodCallExpr = exprTree.Body as MethodCallExpression;
var arguments = items.Skip(1).Select(o => Expression.Constant(o));
var updatedMethod = methodCallExpr.Update(methodCallExpr.Object, arguments);
var updatedLambda = exprTree.Update(updatedMethod, exprTree.Parameters);
mock.Setup(updatedLambda).Returns((TResult)items[0]);
}
}
public static class ArrayExtensions
{
public static void ForEachRow<T>(this T[,] rows, Action<T[]> action)
{
var x = rows.GetLength(1);
var y = rows.GetLength(0);
for (int i = 0; i < y; i++)
{
var row = new T[x];
for (int j = 0; j < x; j++)
{
row[j] = rows[i, j];
}
action(row);
}
}
}
public interface ILogin
{
LoginResult Login(string p1, string p2);
}
public enum LoginResult
{
Success,
WrongPassword,
NoSuchUser
}
EDIT: You asked in a comment about how to take advantage of the variable parameter matching that Moq provides with the It.IsAny<> method. Because what you pass to your Mock.Setup() is an expression tree, it's able to scan the method parameters and implement special behaviour for any that are calls to It.IsAny<>. However, if you use It.IsAny<> in your test data array, by the time we retrieve it from your items array to set in on the expression, it's not a method call but simply the result of the call it It.IsAny<> which is default(T) (see here).
We need some way of specifying in your test data array that the parameter should be any. Then we can check for this special case and generate the correct MethodCallExpression representing a call to It.IsAny<>.
Here are the changes I made to support this:
Add an Any type to use in your test data
public class Any<T>
{
private Any() { }
public static Any<T> Param { get { return new Any<T>(); } }
}
Update the AutoSetup method to handle this special case:
private static void AutoSetup<TMock, TResult>(Mock<TMock> mock, Expression<Func<TMock, TResult>> exprTree, object[] items) where TMock : class
{
var arguments = items.Skip(1).Select(o => {
var type = o.GetType();
if (type.IsGenericType && type.GetGenericTypeDefinition() == typeof(Any<>))
{
var typeParameter = type.GetGenericArguments();
var genericItIsAny = typeof(It).GetMethod("IsAny");
var itIsAny = genericItIsAny.MakeGenericMethod(typeParameter);
return Expression.Call(itIsAny) as Expression;
}
return Expression.Constant(o);
});
var methodCallExpr = exprTree.Body as MethodCallExpression;
var updatedMethod = methodCallExpr.Update(methodCallExpr.Object, arguments);
var updatedLambda = exprTree.Update(updatedMethod, exprTree.Parameters);
mock.Setup(updatedLambda).Returns((TResult)items[0]);
}
In the test data, use the Any type
{ LoginResult.Success, "NoPasswordUser", Any<string>.Param }
Depending on how you're storing your test data, you might need another way of identifying parameters that you want to be variable (specially formatted string?), but in general this should give you an idea about how to create the correct expressions.