[英]How can I use FileSystemWatcher from System.IO.Abstractions to monitor a mock filesystem?
I'm trying to create a class to monitor USB device arrivals and removals on Linux. 我正在尝试创建一个类来监视Linux上USB设备的到来和移除。 On Linux, USB devices are represented as device files under
/dev/bus/usb
which are created/deleted in response to these events. 在Linux上,USB设备表示为
/dev/bus/usb
下的设备文件,这些文件是为响应这些事件而创建/删除的。
It seems the best way to track these events is using FileSystemWatcher
. 似乎最好的跟踪这些事件的方法是使用
FileSystemWatcher
。 To make the class testable, I'm using System.IO.Abstractions
and injecting an instance of IFileSystem
to the class during construction. 为了使该类可测试,我使用了
System.IO.Abstractions
并将IFileSystem
的实例注入到该类中。 What I want is to create something that behaves like a FileSystemWatcher
but monitors changes to the injected IFileSystem
, not the real file-system directly. 我想要创建的行为类似于
FileSystemWatcher
但是监视对注入的IFileSystem
更改,而不是直接监视实际的文件系统。
Looking at FileSystemWatcherBase
and FileSystemWatcherWrapper
from System.IO.Abstractions
, I'm not sure how to do this. 从
System.IO.Abstractions
查看FileSystemWatcherBase
和FileSystemWatcherWrapper
,我不确定如何执行此操作。 At the moment I have this (which I know is wrong): 目前,我有这个(我知道这是错误的):
public DevMonitor(
[NotNull] IFileSystem fileSystem,
[NotNull] IDeviceFileParser deviceFileParser,
[NotNull] ILogger logger,
[NotNull] string devDirectoryPath = DefaultDevDirectoryPath)
{
Raise.ArgumentNullException.IfIsNull(logger, nameof(logger));
Raise.ArgumentNullException.IfIsNull(devDirectoryPath, nameof(devDirectoryPath));
_fileSystem = fileSystem ?? throw new ArgumentNullException(nameof(fileSystem));
_deviceFileParser = deviceFileParser ?? throw new ArgumentNullException(nameof(deviceFileParser));
_logger = logger.ForContext<DevMonitor>();
_watcher = new FileSystemWatcherWrapper(devDirectoryPath);
}
In light of the fact that System.IO.Abstractions
doesn't seem to support this yet, I went with this: 鉴于
System.IO.Abstractions
似乎尚不支持这一点,我同意了:
I defined an IWatchableFileSystem
interface that extends IFileSystem
: 我定义了一个
IWatchableFileSystem
接口,该接口扩展了IFileSystem
:
/// <summary>
/// Represents a(n) <see cref="IFileSystem" /> that can be watched for changes.
/// </summary>
public interface IWatchableFileSystem : IFileSystem
{
/// <summary>
/// Creates a <c>FileSystemWatcher</c> that can be used to monitor changes to this file system.
/// </summary>
/// <returns>A <c>FileSystemWatcher</c>.</returns>
FileSystemWatcherBase CreateWatcher();
}
For production purposes I implement this as WatchableFileSystem
: 出于生产目的,我将其实现为
WatchableFileSystem
:
/// <inheritdoc />
public sealed class WatchableFileSystem : IWatchableFileSystem
{
private readonly IFileSystem _fileSystem;
/// <summary>
/// Initializes a new instance of the <see cref="WatchableFileSystem" /> class.
/// </summary>
public WatchableFileSystem() => _fileSystem = new FileSystem();
/// <inheritdoc />
public DirectoryBase Directory => _fileSystem.Directory;
/// <inheritdoc />
public IDirectoryInfoFactory DirectoryInfo => _fileSystem.DirectoryInfo;
/// <inheritdoc />
public IDriveInfoFactory DriveInfo => _fileSystem.DriveInfo;
/// <inheritdoc />
public FileBase File => _fileSystem.File;
/// <inheritdoc />
public IFileInfoFactory FileInfo => _fileSystem.FileInfo;
/// <inheritdoc />
public PathBase Path => _fileSystem.Path;
/// <inheritdoc />
public FileSystemWatcherBase CreateWatcher() => new FileSystemWatcher();
}
Within my unit test class I implement it as MockWatchableFileSystem
which exposes MockFileSystem
and Mock<FileSystemWatcherBase>
as properties which I can use for arranging & asserting within my tests: 在我的单元测试类中,我将其实现为
MockWatchableFileSystem
,将MockFileSystem
和Mock<FileSystemWatcherBase>
公开为可用于在测试中进行安排和声明的属性:
private class MockWatchableFileSystem : IWatchableFileSystem
{
/// <inheritdoc />
public MockWatchableFileSystem()
{
Watcher = new Mock<FileSystemWatcherBase>();
AsMock = new MockFileSystem();
AsMock.AddDirectory("/dev/bus/usb");
Watcher.SetupAllProperties();
}
public MockFileSystem AsMock { get; }
/// <inheritdoc />
public DirectoryBase Directory => AsMock.Directory;
/// <inheritdoc />
public IDirectoryInfoFactory DirectoryInfo => AsMock.DirectoryInfo;
/// <inheritdoc />
public IDriveInfoFactory DriveInfo => AsMock.DriveInfo;
/// <inheritdoc />
public FileBase File => AsMock.File;
/// <inheritdoc />
public IFileInfoFactory FileInfo => AsMock.FileInfo;
/// <inheritdoc />
public PathBase Path => AsMock.Path;
public Mock<FileSystemWatcherBase> Watcher { get; }
/// <inheritdoc />
public FileSystemWatcherBase CreateWatcher() => Watcher.Object;
}
Finally, in my client class I can just do: 最后,在我的客户类中,我可以做:
public DevMonitor(
[NotNull] IWatchableFileSystem fileSystem,
[NotNull] IDeviceFileParser deviceFileParser,
[NotNull] ILogger logger,
[NotNull] string devDirectoryPath = DefaultDevDirectoryPath)
{
// ...
_watcher = fileSystem.CreateWatcher();
_watcher.IncludeSubdirectories = true;
_watcher.EnableRaisingEvents = true;
_watcher.Path = devDirectoryPath;
}
During tests, the client gets an IWatchableFileSystem
that wraps MockFileSystem
and returns a mock instance of FileSystemWatcherBase
. 在测试过程中,客户端将获得一个
IWatchableFileSystem
,该IWatchableFileSystem
包裹类包装了MockFileSystem
并返回FileSystemWatcherBase
的模拟实例。 During production, it gets an IWatchableFileSystem
that wraps FileSystem
and generates unique instances of FileSystemWatcher
. 在生产过程中,它得到的
IWatchableFileSystem
一个封装FileSystem
,并产生独特的实例FileSystemWatcher
。
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