Can I handle case insensitive string in my mock?

I have the class under test:

public class AppManager {
    public string[] GetAppSets() => Registry.LocalMachine
        .OpenSubKey(@"SOFTWARE\Autodesk\AutoCAD", false)
        ?.GetSubKeyNames();
}

Also, I have the test for GetAppSets method:

[Test]
public void Foo_Returns_ValidValue() {

    const string subkey = @"SOFTWARE\Autodesk\AutoCAD";
    /* The sets of applications which are based on 
     * AutoCAD 2009-2017. */
    string[] fakeSets = new[] { "R17.2", "R18.0",
        "R18.1", "R18.2", "R19.0", "R19.1", "R20.0",
        "R20.1","R21.0" };

    RegistryKey rk = Mock.Create<RegistryKey>();

    Mock.Arrange(() => rk.GetSubKeyNames()).Returns(
        fakeSets);

    Mock.Arrange(() => Registry.LocalMachine.OpenSubKey
    (subkey, false)).Returns(rk);

    AppManager appMng = new AppManager();
    string[] appSets = appMng.GetAppSets();

    Assert.AreEqual(fakeSets, appSets);
}

It works. But my test will be failure if GetAppSets method uses "Software\Autodesk\AutoCAD" or "software\autodesk\autocad" string instead of "SOFTWARE\Autodesk\AutoCAD".

So, at this case either tester needs to know theGetAppSets method implementation (the bad variant), or to handle parameter like the case insensitive string.

Is it possible to use the second variant?