C＃Directory.GetCurrentDirectory（）返回带有NUnit的system32

Question

I am using a 3rd party nuget package for puppeteer. I cant get any code involving this library to work. I looked into the code and found the following line of code

DownloadsFolder = Path.Combine(Directory.GetCurrentDirectory(), ".local-chromium");

The issue is that when I run a unit test Directory.GetCurrentDirectory() returns Windows/system32 and the code fails because it doesn't have permission to write to this directory.

It would seem that this is intended behavior https://github.com/nunit/nunit/issues/1768 . The issue here is that I can't modify the source code of this dll so I am stuck. Is there any way to modify nunit so that it returns a directory that I can define for Directory.GetCurrentDirectory() ?

Answer 1

If I understand correctly, the code that calls Directory.GetCurrentDirectory is in a library used by the application you are testing. (If it were in your own NUnit tests, then this answer would have to be different.) This is a bad design choice for library code, since it assumes that the application calling the library has set (or left) the current directory to the appropriate location. (IMO, it's OK for an application to do this, but not a library.)

I'm guessing that you are running under Visual Studio, since the current directory ends up being System32.

By design, NUnit itself never changes the current directory, so it is left just as it was when the program was first run. You can change it in your tests, but there are risks in doing so.

That explains why you see the problem. Here is a workaround.

1. If you don't care (for test purposes) where the folder is located, create a temp folder in your test setup and remove it in teardown. You can do this for each test (SetUp and TearDown) or for the entire fixture (OneTimeSetUp and OneTimeTearDown).

2. In the same setup location, set the current directory to that temporary folder, saving the original current directory. Restore it in the appropriate teardown method.

3. Ensure that no tests using the directory can run in parallel. If you don't use the ParallelizableAttribute at all you should be OK. But if you have set it to some value at the assembly or other higher level, mark the classes that contain these tests as [NonParallelizable] .

The last step is very important. The current directory is set for the entire process, so it would affect all executing tests. It's important that no other tests run while the changed directory is in effect.