Remove URL normalisation

As a target path is a URL path it's not correct to consider it as
interchangeable with a filepath within every operation system. The
unquote is also removed as the ngclient cannot assume correctly
which encoding is intended and which not

Fixes #1483

Signed-off-by: Ivana Atanasova <iyovcheva@iyovcheva-a02.vmware.com>

Author: Ivana Atanasova

tests/test_fetcher_ng.py

@@ -54,7 +54,7 @@ def setUp(self):
             self.file_contents = target_fileobj.read()
             self.file_length = len(self.file_contents)
 
-        self.rel_target_filepath = os.path.basename(target_filepath)
+        self.rel_target_filepath = os.path.basename(target_filepath).replace("\\","/")
         self.url_prefix = (
             f"http://{utils.TEST_HOST_ADDRESS}:"
             f"{str(self.server_process_handler.port)}"

tuf/ngclient/fetcher.py

@@ -10,7 +10,6 @@
 import tempfile
 from contextlib import contextmanager
 from typing import IO, Iterator
-from urllib import parse
 
 from tuf import exceptions
 
@@ -61,13 +60,6 @@ def download_file(self, url: str, max_length: int) -> Iterator[IO]:
         Yields:
           A TemporaryFile object that points to the contents of 'url'.
         """
-        # 'url.replace('\\', '/')' is needed for compatibility with
-        # Windows-based systems, because they might use back-slashes in place
-        # of forward-slashes. This converts it to the common format.
-        # unquote() replaces %xx escapes in a url with their single-character
-        # equivalent. A back-slash may beencoded as %5c in the url, which
-        # should also be replaced with a forward slash.
-        url = parse.unquote(url).replace("\\", "/")
         logger.debug("Downloading: %s", url)
 
         number_of_bytes_received = 0