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How to mock "new instance"

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Yi asked on 22 Jan 2013, 08:41 AM

Hi There,

Can anyone give me a hand of how to mock internal new instance in my unit test? my method like below:

public List<Driver> SearchByDriverName(string driverName, bool? status)
{
IDriverDAC driverDAC = new DriverDAC();
List<Driver> drivers = new List<Driver>();
drivers = driverDAC.SearchByDriverName(driverName, status);
return drivers;
}

here i want to test this method, the first thing i need to do is mock the DriverDAC (mock driverDAC.SearchByDriverName
method), but the issue is the DriverDAC
is not injected into this class, it is created by new instance, so i can not mock & by pass the SearchByDriverName method,
can anybody give me a light of how to do it? understand it is better to use DI to inject the class,
but due to some special reason by user, we can not change the design structure now.

Thanks!

Suyi

6 Answers, 1 is accepted

answered on 22 Jan 2013, 01:11 PM

To the best of my knowledge that isn't possible. Since there is nothing for JustMock to intercept easily. This is where Inversion of Control and Dependency Injection come in to "save the day". I would suggest looking into a tool such as StructureMap, Ninject, or Unity to handle your inversion of control/DI or create a custom factory method (for all of your objects that you will call new on) and then you can mock the factory methods to return whatever instance you want to have returned.(thereby mocking the new in a roundabout way)

Of course the other option is the simply pass the object in as a method parameter, then you aren't newing it there.....

answered on 22 Jan 2013, 04:09 PM

Hi Yi Su,

Thank you for contacting Telerik support.

A solution to your issue could be the using of JustMocks Future Mocking. You could try the following approach:

var mockedDriverDAC = Mock.Create<DriverDAC>();

var desiredDriverName = ...;
var desiredStatus = ...;

var desiredCollection = ...;

Mock.Arrange(() => mockedDriverDAC.SearchByDriverName(desiredDriverName, desiredStatus)).IgnoreInstance().ReturnsCollection(desiredCollection);

Having this setup in your test will arrange the "SearchByDriverName" method to return your desired collection, no matter the instance.

I hope this helps.

Greetings,
Kaloyan
the Telerik team

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answered on 24 Jan 2013, 09:14 AM

Hi Kaloyan,

Thanks for your reply, but i am still can not make my test working, do justmock have any limitation of partial class?
why i ask this because i write a example and can make it work but when i move to my business class, i found it is not working,
i guess maybe it caused by i have 2 same naming partial class both called "DriverDAC" in my project,
so at the times when i trying to mock DriverDAC, it is not working, parse my code as below

1.My Unit test class

using STB.EP.RBS.Business;

using System.Collections.Generic;

using System;

using STB.EP.RBS.Data;

using STB.EP.RBS.Business.Entities;

//using Microsoft.SharePoint;

using Telerik.JustMock;

#if !NUNIT

using Microsoft.VisualStudio.TestTools.UnitTesting;

using AssertionException = Microsoft.VisualStudio.TestTools.UnitTesting.AssertFailedException;

#else

using NUnit.Framework;

using TestClass = NUnit.Framework.TestFixtureAttribute;

using TestMethod = NUnit.Framework.TestAttribute;

using System.Xml;

#endif

namespace STB.EP.RBS.Test.TransportBooking

{

/**

* This is a test class for DriverComponentTest and is intended

* to contain all DriverComponentTest Unit Tests

*/

[TestClass()]

public class DriverComponentTest

{

List<Driver> driverList;

DriverComponent dc;

/// <summary>

/// Initialize parameters and method

/// </summary>

[TestInitialize]

public void Initialize()

{

driverList = new List<Driver>();

Driver driver = new Driver();

driver.DriverId = 1;

driver.DriverName = "Driver 1";

driver.DrivingLicenses = "SGXXXXX";

driver.MobileNumber = "12345678";

driver.Status = true;

driver.CreatedBy = "admin";

driver.CreatedOn = new DateTime();

driver.Description = "Driver 1";

driverList.Add(driver);

dc = new DriverComponent();

}

[TestMethod()]

public void testSearchByDriverName()

{

var driverDAC = Mock.Create<STB.EP.RBS.Data.DriverDAC>();

Mock.Arrange(() => driverDAC.CheckExistDriver(Arg.IsAny<string>())).IgnoreInstance().Returns(driverList);

Assert.AreEqual(driverList, new DriverDAC().CheckExistDriver(""));

}

[TestMethod()]

public void testExample()

{

var u = Mock.Create<SubUnitTest>();

Mock.Arrange(() => u.getMessage(Arg.IsAny<string>())).IgnoreInstance().Returns("123");

Assert.AreEqual("123", new unitTest().getStr("test"));

}

public class unitTest

{

public string getStr(string test)

{

SubUnitTest sub = new SubUnitTest();

return sub.getMessage(test);

}

public class SubUnitTest

{

public string getMessage(String str)

{

return str;

}

2.Mocking class of "DriverDAC"

using System;

using System.Collections.Generic;

using System.Collections.ObjectModel;

using System.Linq;

using System.Text;

using System.Data;

using System.Data.Common;

using Microsoft.Practices.EnterpriseLibrary.Data;

using STB.EP.RBS.Business.Entities;

namespace STB.EP.RBS.Data

{

/// <summary>

/// Driver data access component for customization.

/// </summary>

public partial class DriverDAC : DataAccessComponent

{

public virtual List<Driver> CheckExistDriver(string driverName)

{

DbCommand dbCommand = ConnectionHelper.DbConnection.GetStoredProcCommand(Constants.PRC_Driver_CheckExistDriver);

List<Driver> results = new List<Driver>();

ConnectionHelper.DbConnection.AddInParameter(dbCommand, "DriverName", DbType.String, driverName);

using (IDataReader dr = ConnectionHelper.DbConnection.ExecuteReader(dbCommand))

{

while (dr.Read())

{

results.Add(GetDataRow(dr));

}

return results;

}

2.1 Another Mocking class , same name as "DriverDAC"

using System;

using System.Collections.Generic;

using System.Collections.ObjectModel;

using System.Linq;

using System.Text;

using System.Data;

using System.Data.Common;

using Microsoft.Practices.EnterpriseLibrary.Data;

using STB.EP.RBS.Business.Entities;

namespace STB.EP.RBS.Data

{

public partial class DriverDAC : DataAccessComponent

{

/// <summary>

/// Inserts a new row in the Driver table.

/// </summary>

/// <param name="roomBooking">A Driver object.</param>

/// <returns>An updated Driver object.</returns>

public Driver Create( Driver driver)

{

DbCommand dbCommand = ConnectionHelper.DbConnection.GetStoredProcCommand(Constants.PRC_Driver_Insert);

ConnectionHelper.DbConnection.AddInParameter(dbCommand, "DriverName", DbType.String, driver.DriverName);

ConnectionHelper.DbConnection.AddInParameter(dbCommand, "DrivingLicenses", DbType.String, driver.DrivingLicenses);

ConnectionHelper.DbConnection.AddInParameter(dbCommand, "MobileNumber", DbType.String, driver.MobileNumber);

ConnectionHelper.DbConnection.AddInParameter(dbCommand, "Status", DbType.Boolean, driver.Status);

ConnectionHelper.DbConnection.AddInParameter(dbCommand, "CreatedBy", DbType.String, driver.CreatedBy);

ConnectionHelper.DbConnection.AddInParameter(dbCommand, "ModifiedBy", DbType.String, driver.ModifiedBy);

ConnectionHelper.DbConnection.AddInParameter(dbCommand, "Description", DbType.String, driver.Description);

ConnectionHelper.DbConnection.AddInParameter(dbCommand, "OldDriverId", DbType.Guid, driver.OldDriverId);

object obj = ConnectionHelper.DbConnection.ExecuteScalar(dbCommand);

driver.DriverId = Convert.ToInt16(obj);

return driver;

}

/// <summary>

/// Updates an existing row in the Driver table.

/// </summary>

/// <param name="driver">A Driver entity object.</param>

public void UpdateById( Driver driver)

{

DbCommand dbCommand = ConnectionHelper.DbConnection.GetStoredProcCommand(Constants.PRC_Driver_Update);

ConnectionHelper.DbConnection.AddInParameter(dbCommand, "DriverId", DbType.Int16, driver.DriverId);