How to write a proper unit test

How would you write a proper unit test around this method?

public bool ValidateMemoryUnitPath(string path)
{
  var isValidName = Regex.Matches(path, @"^[a-zA-Z0-9_\-:.,+$]").Count == path.Length;

  var isValidFormat = DriveInfo.GetDrives()
                                             .Any(d => d.DriveType == DriveType.Removable
                                                       && d.Name == path
                                                       && (d.DriveFormat == "FAT16" || d.DriveFormat == "FAT"));

  return isValidName && isValidFormat;
}

Below I have listed a test method with a comment where my confusion is

[TestMethod]
public void ValidateMemoryUnitPathReturnsTrue()
{
            // arrange
            const string validPath = "MemoryUnitTest.txt";
            var sut = new CardInitializer();

            // WHAT IS THE CORRECT WAY TO DO THIS
            var drive = Mock.Create<DriveInfo>();
            drive.Arrange(x => x.Name).Returns(validPath);
            drive.Arrange(x => x.DriveFormat).Returns("FAT16");

            // assert
            Assert.IsTrue(sut.ValidateMemoryUnitPath(validPath));
}