public void hash_by_modified_is_dependent_upon_the_last_modified_time()
{
var file1 = "a.txt";
new FileSystem().WriteStringToFile(file1, "something");
Thread.Sleep(1000);
var hash1 = file1.HashByModifiedDate();
new FileSystem().WriteStringToFile(file1, "else");
Thread.Sleep(1000);
var hash2 = file1.HashByModifiedDate();
hash1.ShouldNotBe(hash2);
}