模拟 - 虽然 setup.Returns(true) 但总是得到 false

Question

I have code snippet as following. Although setup with retrurn true but value always return false.

Could someone advise how to retrieve value as true?

public interface IDatabaseService
  {
    bool ProcessSQL(INApplicationProcessDTO inApplicationProcessDTO, string connectionString, string storedProcedureName);
    bool CompleteRun(INApplicationProcessDTO inApplicationProcessDTO, string connectionString, string storedProcedureName);
  }

----CLASS----------

public static class INHelper
{
    public static bool CompleteRun(INApplicationProcessDTO inApplicationProcessDTO, string connectionString = null, IDatabaseService databaseService = null)
    {
      if (inApplicationProcessDTO == null)
      {
        return false;
      }
      if (inApplicationProcessDTO.Data == null)
      {
        return false;
      }
      const string storedProcedureName = "PSP_PWS_INApplication_Application_Process_CompleteRun";

      // Get Connection String to Parity4 Database from Parity4 WebService Web.config
      if (connectionString == null)
      {
        if (ConfigurationManager.ConnectionStrings["ConnectionString"] != null)
        {
          connectionString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        }
      }
      if (string.IsNullOrWhiteSpace(connectionString))
      {
        return false;
      }

      if (databaseService == null)
      {
        databaseService = new DatabaseService();
      }
      //Why always return false line below
      return databaseService.CompleteRun(inApplicationProcessDTO, connectionString, storedProcedureName);
    }
}

----TEST METHOD----

public void When_CompleteRun_ConnectionValid_Expect_True()
    {
      var iNApplicationProcessDTOTest = new INApplicationProcessDTO()
      {
        Data = new System.Xml.Linq.XDocument(),
        ErrorCount = 0,
        Errors = ""
      };

      Mock<IDatabaseService> iDatabaseService = null;
      iDatabaseService = new Mock<IDatabaseService>();
      iDatabaseService.Setup(t => t.CompleteRun(iNApplicationProcessDTOTest, "test", "test")).Returns(true);
      iDatabaseService.Setup(t => t.ProcessSQL(iNApplicationProcessDTOTest, "test", "test")).Returns(true);

      var iNApplicationProcessDTO = new INApplicationProcessDTO()
      {
        Data = new System.Xml.Linq.XDocument(),
        ErrorCount = 0,
        Errors = ""
      };
      var actual = INHelper.CompleteRun(iNApplicationProcessDTO, "a", iDatabaseService.Object);
      //actual always false although Returns(true) in Setup
      Assert.AreEqual(true, actual);
    }        

Appreciate your help.

Answer 1

There are a couple of tiny problems with your Test code.

First let me show how you should implement it and then let me give you some explanation:

[Fact]
public void GivenAFlawlessDatabaseService_WhenICallCompleteRun_ThenItCallsTheUnderlyingServicesCompleteRun()
{
    //Arrange
    const string connectionString = "a";
    var iDatabaseService = new Mock<IDatabaseService>();

    iDatabaseService
        .Setup(db => db.CompleteRun(It.IsAny<INApplicationProcessDTO>(), It.IsAny<string>(), It.IsAny<string>()))
        .Returns(true);

    var iNApplicationProcessDTO = new INApplicationProcessDTO
    {
        Data = new XDocument(),
        ErrorCount = 0,
        Errors = ""
    };

    //Act
    var actual = INHelper.CompleteRun(iNApplicationProcessDTO, connectionString, iDatabaseService.Object);
    
    //Assert
    Assert.True(actual);
    iDatabaseService.Verify(db => db.CompleteRun(iNApplicationProcessDTO, connectionString, "PSP_PWS_INApplication_Application_Process_CompleteRun"), Times.Once);
    iDatabaseService.Verify(db => db.ProcessSQL(It.IsAny<INApplicationProcessDTO>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never);
}

• First, I would suggest to use somewhat more meaningful names for your tests. Here I've used a Given When Then structure to describe under what circumstances (given) if a specific action is triggered (when) what would I expect (then)
• I also suggest to use the Arrange , Act and Assert comments to separate different phases of your test case visually
• The Setup method calls normally do not rely on concrete objects. The reason behind it is that classes are compared by reference. So, even if you have two seemingly identical instances (like: iNApplicationProcessDTOTest and iNApplicationProcessDTO ) they are different. That's why the mock function is not being called.
  • Use It.IsAny<T>() calls in the Setup phase and use concrete values in the Verify phase.
• If one of the methods of the mocked object is not called by the SUT (system under test) then you don't need to Setup it.
  • But you can still verify that it has not been called ( Verify(..., Times.Never); )