C＃如何模拟对象列表

Question

In C#, How do I go about mocking a list of objects?

I am attempting an exercise and it specifies that in the arrange section of my unit test that I need to "mock a List of Book objects".

What is the syntax for creating a mock list of Book objects? I have tried creating mock Book objects and adding them to a list of books but this didn't work.

public void Test_GetAllBooks_ReturnsListOfBooksItReceivesFromReadAllMethodOfReadItemCommand_WhenCalled()
{
    //Arrange
    Mock<ReadItemCommand> mockReadItemCommand = new Mock<ReadItemCommand>();
    Catalogue catalogue = new Catalogue(mockReadItemCommand.Object);

    Mock<Book> mockBook1 = new Mock<Book>();
    Mock<Book> mockBook2 = new Mock<Book>();
    List<Book> mockBookList = new List<Book>();
    mockBookList.Add(mockBook1);
    mockBookList.Add(mockBook2);

    mockReadItemCommand.Setup(r => r.ReadAll()).Returns(mockBookList);

    //Act
    List<Book> actual = catalogue.GetAllBooks();

    //Assert
    Assert.AreSame(mockBookList, actual);

}

This is giving me 2 compilation errors, both CS1503, on the two lines where I have tried to add the mock books to my list of type Book.

Answer 1

Just create a list of books to represent fake/mocked data to be returned when exercising the method under test. No need to use Moq for the fake data. Use Moq to mock the dependencies ( ReadItemCommand ) of the system under test ( Catalogue )

public void Test_GetAllBooks_ReturnsListOfBooksItReceivesFromReadAllMethodOfReadItemCommand_WhenCalled()
{
    //Arrange
    var mockReadItemCommand = new Mock<ReadItemCommand>();
    var catalogue = new Catalogue(mockReadItemCommand.Object);

    var expected = new List<Book>(){
        new Book {
            Title = "Book1", 
            //populate other properties  
        },
        new Book { 
            Title = "Book2", 
            //populate other properties  
        }
    };

    mockReadItemCommand
        .Setup(_ => _.ReadAll())
        .Returns(expected);

    //Act
    var actual = catalogue.GetAllBooks();

    //Assert
    Assert.AreSame(expected, actual);
}

Answer 2

if i got you right,you can clone the list: for example as shown here:

How do I clone a generic list in C#?

you can clone it in the same way,or instead you can copy the list yourself by creating a new list and add a copy of each element from the source list. hope it helps.