Using File.Create and Delete with unit tests, but getting "file used by other process" exception

Question

I have this unit test:

   [Test]
   public void ProcessDbFile_should_delete_file_if_it_exists_then_copy_new_file_to_same_location()
   {
       // used to create condition where file already exists
       if (!File.Exists(path2))
            File.Create(path2);
       _dbInstaller.ProcessDbFile(path1);
       File.Exists(path2).ShouldBe(true);
       errorReceived.ShouldBe(null);
   }

what's happening is when I get to this part inside the ProcessDbFile routine:

   if (File.Exists(path2))
       _dbDropper.DropDb();

which then goes to this:

public bool DropDbStub()
{
   try
   {
      File.Delete(@"c:\dbdata\data.mdf");
   }
   catch
   {
      return false;
   }
  return true;
}

I get the exception that the file is being used by another process.

I guess my main question is the Unit Test a separate process?

If I comment out the first 2 lines of the unit test:

// if (!File.Exists(path2)) // File.Create(path2);

I do not get the exception, even if the file is there already, the deletion happens as planned, only when I have these first 2 lines in the unit tests (and it does jump into the Create line, somehow the unit test seems to have a lock on the file. What can I do to overcome this, to keep the test working as it should, which is to test deleting a file if it already exists, and to create it first if it didn't exist already?

Answer 1

File.Create(path2) opens a stream to that file that you never close.

Your code should be:

if (!File.Exists(path2))
    File.Create(path2).Close();