Update test_download

Replace tuf.download with a tuf.download.FileDownload() object.

Signed-off-by: Teodora Sechkova <tsechkova@vmware.com>

Author: sechkova

tests/test_download.py

@@ -42,7 +42,7 @@
 import warnings
 
 import tuf
-import tuf.download as download
+import tuf.download
 import tuf.log
 import tuf.unittest_toolbox as unittest_toolbox
 import tuf.exceptions
@@ -85,6 +85,9 @@ def setUp(self):
     digest = m.hexdigest()
     self.target_hash = {'md5':digest}
 
+    # Create a 'FileDownload' object with the default 'RequestsFetcher'
+    self.download = tuf.download.FileDownload()
+
 
   # Stop server process and perform clean up.
   def tearDown(self):
@@ -99,7 +102,7 @@ def tearDown(self):
   # Test: Normal case.
   def test_download_url_to_tempfileobj(self):
 
-    download_file = download.safe_download
+    download_file = self.download.safe_download
     with download_file(self.url, self.target_data_length) as temp_fileobj:
       temp_fileobj.seek(0)
       temp_file_data = temp_fileobj.read().decode('utf-8')
@@ -118,18 +121,18 @@ def test_download_url_to_tempfileobj_and_lengths(self):
     # the server-reported length of the file does not match the
     # required_length.  'updater.py' *does* verify the hashes of downloaded
     # content.
-    download.safe_download(self.url, self.target_data_length - 4).close()
-    download.unsafe_download(self.url, self.target_data_length - 4).close()
+    self.download.safe_download(self.url, self.target_data_length - 4).close()
+    self.download.unsafe_download(self.url, self.target_data_length - 4).close()
 
     # We catch 'tuf.exceptions.DownloadLengthMismatchError' for safe_download()
     # because it will not download more bytes than requested (in this case, a
     # length greater than the size of the target file).
     self.assertRaises(tuf.exceptions.DownloadLengthMismatchError,
-        download.safe_download, self.url, self.target_data_length + 1)
+        self.download.safe_download, self.url, self.target_data_length + 1)
 
     # Calling unsafe_download() with a mismatched length should not raise an
     # exception.
-    download.unsafe_download(self.url, self.target_data_length + 1).close()
+    self.download.unsafe_download(self.url, self.target_data_length + 1).close()
 
 
 
@@ -161,16 +164,12 @@ def test_download_url_to_tempfileobj_and_performance(self):
   # Test: Incorrect/Unreachable URLs.
   def test_download_url_to_tempfileobj_and_urls(self):
 
-    download_file = download.safe_download
-    unsafe_download_file = download.unsafe_download
+    download_file = self.download.safe_download
+    unsafe_download_file = self.download.unsafe_download
 
     self.assertRaises(securesystemslib.exceptions.FormatError,
                       download_file, None, self.target_data_length)
 
-    self.assertRaises(tuf.exceptions.URLParsingError,
-                      download_file,
-                      self.random_string(), self.target_data_length)
-
     url = 'http://localhost:' \
         + str(self.server_process_handler.port) + '/' + self.random_string()
     self.assertRaises(requests.exceptions.HTTPError,
@@ -213,10 +212,10 @@ def test_https_validation(self):
         'https://wrong.host.badssl.com/', ]: # hostname verification fail
 
       with self.assertRaises(requests.exceptions.SSLError):
-        download.safe_download(bad_url, irrelevant_length)
+        self.download.safe_download(bad_url, irrelevant_length)
 
       with self.assertRaises(requests.exceptions.SSLError):
-        download.unsafe_download(bad_url, irrelevant_length)
+        self.download.unsafe_download(bad_url, irrelevant_length)
   '''
 
 
@@ -302,25 +301,25 @@ def test_https_connection(self):
             category=urllib3.exceptions.SubjectAltNameWarning)
 
         with self.assertRaises(requests.exceptions.SSLError):
-          download.safe_download(bad_https_url, target_data_length)
+          self.download.safe_download(bad_https_url, target_data_length)
         with self.assertRaises(requests.exceptions.SSLError):
-          download.unsafe_download(bad_https_url, target_data_length)
+          self.download.unsafe_download(bad_https_url, target_data_length)
 
         # Try connecting to the server processes with the good certs while not
         # trusting the good certs (trusting the bad cert instead). Expect failure
         # because even though the server's cert file is otherwise OK, we don't
         # trust it.
         logger.info('Trying HTTPS download of target file: ' + good_https_url)
         with self.assertRaises(requests.exceptions.SSLError):
-          download.safe_download(good_https_url, target_data_length)
+          self.download.safe_download(good_https_url, target_data_length)
         with self.assertRaises(requests.exceptions.SSLError):
-          download.unsafe_download(good_https_url, target_data_length)
+          self.download.unsafe_download(good_https_url, target_data_length)
 
         logger.info('Trying HTTPS download of target file: ' + good2_https_url)
         with self.assertRaises(requests.exceptions.SSLError):
-          download.safe_download(good2_https_url, target_data_length)
+          self.download.safe_download(good2_https_url, target_data_length)
         with self.assertRaises(requests.exceptions.SSLError):
-          download.unsafe_download(good2_https_url, target_data_length)
+          self.download.unsafe_download(good2_https_url, target_data_length)
 
 
         # Configure environment to now trust the certfile that is expired.
@@ -334,9 +333,9 @@ def test_https_connection(self):
         # it, it is expired.
         logger.info('Trying HTTPS download of target file: ' + expired_https_url)
         with self.assertRaises(requests.exceptions.SSLError):
-          download.safe_download(expired_https_url, target_data_length)
+          self.download.safe_download(expired_https_url, target_data_length)
         with self.assertRaises(requests.exceptions.SSLError):
-          download.unsafe_download(expired_https_url, target_data_length)
+          self.download.unsafe_download(expired_https_url, target_data_length)
 
 
         # Try connecting to the server processes with the good certs while
@@ -348,16 +347,16 @@ def test_https_connection(self):
         # TODO: Confirm necessity of this session clearing and lay out mechanics.
         tuf.download._sessions = {}
         logger.info('Trying HTTPS download of target file: ' + good_https_url)
-        download.safe_download(good_https_url, target_data_length).close()
-        download.unsafe_download(good_https_url, target_data_length).close()
+        self.download.safe_download(good_https_url, target_data_length).close()
+        self.download.unsafe_download(good_https_url, target_data_length).close()
 
         os.environ['REQUESTS_CA_BUNDLE'] = good2_cert_fname
         # Clear sessions to ensure that the certificate we just specified is used.
         # TODO: Confirm necessity of this session clearing and lay out mechanics.
         tuf.download._sessions = {}
         logger.info('Trying HTTPS download of target file: ' + good2_https_url)
-        download.safe_download(good2_https_url, target_data_length).close()
-        download.unsafe_download(good2_https_url, target_data_length).close()
+        self.download.safe_download(good2_https_url, target_data_length).close()
+        self.download.unsafe_download(good2_https_url, target_data_length).close()
 
     finally:
       for proc_handler in [