单元测试文件I / O [英] Unit Testing File I/O

问题描述

通过这里对堆栈溢出现有的单元测试相关的主题阅读，我无法找到一个有关单位如何测试文件I / O操作一个明确的答案。我最近才开始寻找到单元测试，虽然已经previously意识到的优点，​​但有困难的习惯编写测试第一。我已经建立了我的项目使用NUnit的和犀牛制品，虽然我知道他们背后的概念，我有一个小麻烦了解如何使用模拟对象。

Reading through the existing unit testing related threads here on Stack Overflow, I couldn't find one with a clear answer about how to unit test file I/O operations. I have only recently started looking into unit testing, having been previously aware of the advantages but having difficulty getting used to writing tests first. I have set up my project to use NUnit and Rhino Mocks and although I understand the concept behind them, I'm having a little trouble understanding how to use Mock Objects.

具体来说，我有，我想回答两个问题。首先，什么是单元测试文件I / O操作的正确方法？其次，我试图了解单元测试，我所遇到的依赖注入。获得后Ninject设置和工作，我不知道我是否应该我的单元测试中使用DI，或者只是直接实例化对象。

Specifically I have two questions that I would like answered. First, what is the proper way to unit test file I/O operations? Second, in my attempts to learn about unit testing, I have come across dependency injection. After getting Ninject set up and working, I was wondering whether I should use DI within my unit tests, or just instantiate objects directly.

推荐答案

查看<一个href=\"http://vkreynin.word$p$pss.com/2008/12/04/tutorial-to-tdd-using-rhino-mocks-and-systemwrapper/\">Tutorial以TDD 使用犀牛制品并的SystemWrapper 。

SystemWrapper包装许多System.IO类，包括文件，FileInfo的，目录和Dir​​ectoryInfo，...的。你可以看到完整列表。

SystemWrapper wraps many of System.IO classes including File, FileInfo, Directory, DirectoryInfo, ... . You can see the complete list.

在本教程中，我展示了如何做测试用MbUnit的，但它正是为NUnit的一样。

In this tutorial I'm showing how to do testing with MbUnit but it's exactly the same for NUnit.

您的测试将会是这个样子：

Your test is going to look something like this:

[Test]
public void When_try_to_create_directory_that_already_exists_return_false()
{
    var directoryInfoStub = MockRepository.GenerateStub<IDirectoryInfoWrap>();
    directoryInfoStub.Stub(x => x.Exists).Return(true);
    Assert.AreEqual(false, new DirectoryInfoSample().TryToCreateDirectory(directoryInfoStub));

    directoryInfoStub.AssertWasNotCalled(x => x.Create());
}

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