NUnit运行多个程序集时Assembly.GetExecutingAssembly的意外位置

Question

I recently encountered an odd issue when performing unit tests. My solution contains a helper class with a property for getting the directory of the executing assembly. It looks like this:

public static class DirectoryHelper
{
    public static string ExecutingAssemblyDirectory
    {
        get
        {
            var codeBase = Assembly.GetExecutingAssembly().CodeBase;
            var uri = new UriBuilder(codeBase);
            var path = Uri.UnescapeDataString(uri.Path);
            return Path.GetDirectoryName(path);
        }
    }
}

This method is called through various test classes to get relative file paths to dependent resources.

Take the following contrived projects as examples:

TestProject1.dll - TestFixture1.cs

[TestFixture]
public class TestFixture1
{
    [Test]
    public void VerifyExecutingAssemblyDirectory1()
    {
        StringAssert.Contains(@"\TestProject1\bin\Debug", 
        DirectoryHelper.ExecutingAssemblyDirectory);
    }
}

TestProject2.dll - TestFixture2.cs

[TestFixture]
public class TestFixture2
{
    [Test]
    public void VerifyExecutingAssemblyDirectory1()
    {
        StringAssert.Contains(@"TestProject2\bin\Debug", 
        DirectoryHelper.ExecutingAssemblyDirectory);
    }
}

When these tests are ran individually they pass and the location of the returned assembly is the debug folder of the test class.

However, when ran together, TestFixture2.VerifyExecutingAssemblyDirectory2() is actually returning the path to the bin folder of TestProject1 , rather than TestProject2 .

I'm trying to determine why this behavior is happening and understand a better way of going about this. I've found that using .GetCallingAssembly will resolve this problem, but it doesn't seem like I should have to do this.

I've created an example to reproduce this issue and posted to GitHub. TylerNielsen/NUnitExecutingAssemblyExample

Note: I'm aware of the TestContext.TestDirectory in NUnit, however this library is currently not dependent on NUnit and I'd prefer to keep it that way.

UPDATE I'm running the NUnit tests through both Resharper in Visual Studio and via NUnit3-Console. When I run using NUnit3-Console, I'm only specifying the two individual .dlls and not providing any other arguments.

Answer 1

Both TestProject1 and TestProject2 reference the assembly containing DirectoryHelper. I'm assuming that your references cause the assembly to be copied to the individual (separate) output directories.

When you run both test assemblies together, one of them causes it's "personal" copy of that assembly to be loaded. The second one finds that the assembly is already in memory.

Of course, this behavior will depend on how you run the assemblies, which you haven't said. In the case where you use nunit3-console, it will also depend on your command-line arguments, especially whether you use a separate process for each assembly.