避免竞争条件创建StorageFolder
本文关键字:创建 StorageFolder 条件 竞争 | 更新日期: 2023-09-27 17:51:26
我正在单元测试一个新的Win8 Store应用程序,并注意到一个我想要避免的竞争条件。所以我正在寻找一种方法来避免这种竞争条件。
我有一个类,当实例化调用一个方法,以确保它有一个本地的StorageFolder。我的单元测试只是实例化对象并测试文件夹是否存在。有时文件夹不是,有时它是,所以我认为这是一个竞争条件,因为CreateFolderAsync是异步的(显然)。
public class Class1
{
StorageFolder _localFolder = null;
public Class1()
{
_localFolder = ApplicationData.Current.LocalFolder;
_setUpStorageFolders();
}
public StorageFolder _LocalFolder
{
get
{
return _localFolder;
}
}
async void _setUpStorageFolders()
{
try
{
_localFolder = await _localFolder.CreateFolderAsync("TestFolder", CreationCollisionOption.FailIfExists);
}
catch (Exception)
{
throw;
}
}
}
我的单元测试是这样的:
[TestMethod]
public void _LocalFolder_Test()
{
Class1 ke = new Class1();
// TODO: Fix Race Condition
StorageFolder folder = ke._LocalFolder;
string folderName = folder.Name;
Assert.IsTrue(folderName == "TestFolder");
}
按照Iboshuizen的建议,我将同步执行此操作。这可以用async
, task
和await
来完成。这里有一个问题——设置不能在Class1
的构造函数中完成,因为构造函数不支持async/await。因此,SetUpStorageFolders
现在是公共的,并从测试方法中调用。
public class Class1
{
StorageFolder _localFolder = null;
public Class1()
{
_localFolder = ApplicationData.Current.LocalFolder;
// call to setup removed here because constructors
// do not support async/ await keywords
}
public StorageFolder _LocalFolder
{
get
{
return _localFolder;
}
}
// now public... (note Task return type)
async public Task SetUpStorageFolders()
{
try
{
_localFolder = await _localFolder.CreateFolderAsync("TestFolder", CreationCollisionOption.FailIfExists);
}
catch (Exception)
{
throw;
}
}
}
测试: // note the signature change here (async + Task)
[TestMethod]
async public Task _LocalFolder_Test()
{
Class1 ke = new Class1();
// synchronous call to SetupStorageFolders - note the await
await ke.SetUpStorageFolders();
StorageFolder folder = ke._LocalFolder;
string folderName = folder.Name;
Assert.IsTrue(folderName == "TestFolder");
}