我希望创建一个工厂,用于为我的单元测试创建常见的模拟对象。我已经成功设置了我的测试,可以模拟 Linq2Sql DataContext 并返回内存表而不是访问数据库。我是这样设置的:
_contactsTable = new InMemoryTable<Contact>(new List<Contact>());
_contactEmailsTable = new InMemoryTable<ContactEmail>(new List<ContactEmail>());
// repeat this for each table in the ContactsDataContext
var mockContext = new Mock<ContactsDataContext>();
mockContext.Setup(c => c.Contacts).Returns(_contactsTable);
mockContext.Setup(c => c.ContactEmails).Returns(_contactEmailsTable);
// repeat this for each table in the ContactsDataContext
如果DataContext包含很多表,使用它会变得繁琐。因此,我认为可以使用一个简单的工厂方法,利用反射从DataContext中获取所有表:
public static DataContext GetMockContext(Type contextType)
{
var instance = new Mock<DataContext>();
var propertyInfos = contextType.GetProperties();
foreach (var table in propertyInfos)
{
//I'm only worried about ITable<> now, otherwise skip it
if ((!table.PropertyType.IsGenericType) ||
table.PropertyType.GetGenericTypeDefinition() != typeof (ITable<>)) continue;
//Determine the generic type of the ITable<>
var TableType = GetTableType(table);
//Create a List<T> of that type
var emptyList = CreateGeneric(typeof (List<>), TableType);
//Create my InMemoryTable<T> of that type
var inMemoryTable = CreateGeneric(typeof (InMemoryTable<>), TableType, emptyList);
//NOW SETUP MOCK TO RETURN THAT TABLE
//How do I call instance.Setup(i=>i.THEPROPERTYNAME).Returns(inMemoryTable) ??
}
return instance.Object;
}
到目前为止,我已经知道如何创建我需要设置Mock的对象,但我就是无法找出如何动态调用Moq的Setup()方法并传入属性名称。我开始研究反射来调用Moq的Setup()方法,但很快就变得非常丑陋。
有没有人有一个简单的方法来像这样动态调用Setup()和Returns()?
编辑:Brian的答案让我明白了。以下是它的工作原理:
public static DataContext GetMockContext<T>() where T: DataContext
{
Type contextType = typeof (T);
var instance = new Mock<T>();
var propertyInfos = contextType.GetProperties();
foreach (var table in propertyInfos)
{
//I'm only worried about ITable<> now, otherwise skip it
if ((!table.PropertyType.IsGenericType) ||
table.PropertyType.GetGenericTypeDefinition() != typeof(ITable<>)) continue;
//Determine the generic type of the ITable<>
var TableType = GetTableType(table);
//Create a List<T> of that type
var emptyList = CreateGeneric(typeof(List<>), TableType);
//Create my InMemoryTable<T> of that type
var inMemoryTable = CreateGeneric(typeof(InMemoryTable<>), TableType, emptyList);
//NOW SETUP MOCK TO RETURN THAT TABLE
var parameter = Expression.Parameter(contextType);
var body = Expression.PropertyOrField(parameter, table.Name);
var lambdaExpression = Expression.Lambda<Func<T, object>>(body, parameter);
instance.Setup(lambdaExpression).Returns(inMemoryTable);
}
return instance.Object;
}