How to Unit Test a Protected Method with database connection inside a public method in C#?

Question

I have the following scenario:

public class Child : Parent
{

private int _eventTypeId;
 public override Dictionary<string, dynamic> Execute(IDynamicDatabaseConnection dbConn, IDbTransaction dbTrans)
        {
_eventTypeId = GetEventType(dbConn, dbTrans);
}
}

public abstract class Parent : ParentInterface
    {
protected int GetEventType(IDynamicDatabaseConnection dbConn, IDbTransaction dbTrans) => GetItemId("EventType", "User Initiated", dbConn, dbTrans);

 protected int GetItemId(string param1, string param2, IDynamicDatabaseConnection dbConn, IDbTransaction dbTrans) =>
            dbConn.Query<int>(
                $@"myQuery",
                dbTrans).FirstOrDefault();


public abstract Dictionary<string, dynamic> Execute(IDynamicDatabaseConnection dbConn, IDbTransaction dbTrans);
}

    public interface ParentInterface
    {
        Dictionary<string, dynamic> Execute(IDynamicDatabaseConnection dbConn, IDbTransaction dbTrans);
    }

How should I be mocking the GetEventType method from my child class?

I use mocking in the following way.

            var connMock = A.Fake<IDynamicDatabaseConnection>();
            var transMock = A.Fake<IDbTransaction>();
            A.CallTo(() => connMock.BeginTransaction()).Returns(transMock);
A.CallTo(() => dbConnMock.Query<string>(null, null, null, A<bool>._, null, null)).WithAnyArguments().Returns(new List<string>() { "AfterSaveSPName" });

Update: Adding the Child Class Test Method which I am testing.

        [TestMethod]
        public void Initiate_Intake_Should_Insert_FormMode_Initiate()
        {
            // Arrange
            Dictionary<string, dynamic> childParameters = new Dictionary<string, dynamic>
            {
                 {Key, -1}
            };
            var dynamicAssembly = A.Fake<IDynamicAssembly>();
            var connMock = A.Fake<IDynamicDatabaseConnection>();
            var transMock = A.Fake<IDbTransaction>();
            var fakeInitiateIntake = A.Fake<InitiateBase>(options => options.Implements<IInitiateBase>());
            
A.CallTo(() => connMock.BeginTransaction()).Returns(transMock);
            A.CallTo(fakeInitiateIntake).Where(call => call.Method.Name == "GetEventType")
                .WithReturnType<int>()
                .Returns(197);

            // Act
            var child = new Child(childParameters, dynamicAssembly);
            child.Execute(connMock, transMock);

            // Assert
            initiateParameters["Key"].Equals(1234);
        }

Answer 1

You haven't said, but I'm assuming you're trying to test Child.

First, note that FakeItEasy will not be able to intercept calls to GetEventType unless the method is virtual or abstract. If you're able to make that change, you can follow the instructions at Specifying a call to any method or property, which shows an example using a protected method's name to identify it. You'll end up with something like this:

A.CallTo(fakeChild).Where(call => call.Method.Name == "GetEventType")
                   .WithReturnType<int>()
                   .Returns(197);