[tor-commits] [stem/master] Add RawRelayCell and temp-fix RelayCell tests (interim)

[atagar at torproject.org]

commit 5d86cbde132d7912c411d9134eee6cc05b745d94
Author: Dave Rolek <dmr-x at riseup.net>
Date:   Wed Aug 8 01:14:27 2018 +0000

    Add RawRelayCell and temp-fix RelayCell tests (interim)
    
    Notably, this along with CANNOT_DIRECTLY_UNPACK for RelayCell (prior
    change) allows Cell.pop() and Cell.unpack() to be executed directly on
    received bytes from a connection, and still process encrypted cells
    correctly into RELAY cells, to be decrypted later.
    
    RelayCell tests marked with TODO where temp-fix was applied.
    
    RelayCell implementation will gradually be improved/refactored into
    better supporting subclasses per command.
---
 stem/client/cell.py      |  5 +++++
 test/unit/client/cell.py | 34 ++++++++++++++++++++++++----------
 2 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/stem/client/cell.py b/stem/client/cell.py
index dcebc544..4f7aec79 100644
--- a/stem/client/cell.py
+++ b/stem/client/cell.py
@@ -356,6 +356,11 @@ class BaseRelayCell(CircuitCell):
     return stem.util._hash_attr(self, 'circ_id', 'payload', cache = True)
 
 
+class RawRelayCell(BaseRelayCell):
+  NAME = 'RELAY'
+  VALUE = 3
+
+
 class RelayCell(CircuitCell):
   """
   Command concerning a relay circuit.
diff --git a/test/unit/client/cell.py b/test/unit/client/cell.py
index b8fe58df..3e091ee5 100644
--- a/test/unit/client/cell.py
+++ b/test/unit/client/cell.py
@@ -15,6 +15,7 @@ from stem.client.cell import (
   Cell,
   PaddingCell,
   BaseRelayCell,
+  RawRelayCell,
   RelayCell,
   DestroyCell,
   CreateFastCell,
@@ -93,20 +94,24 @@ AUTH_CHALLENGE_CELLS = {
 
 class TestCell(unittest.TestCase):
   def test_by_name(self):
-    cls = Cell.by_name('NETINFO')
-    self.assertEqual('NETINFO', cls.NAME)
-    self.assertEqual(8, cls.VALUE)
-    self.assertEqual(True, cls.IS_FIXED_SIZE)
+    for (expected_class, name, value, is_fixed_size) in ((NetinfoCell, 'NETINFO', 8, True), (RawRelayCell, 'RELAY', 3, True)):
+      cls = Cell.by_name(name)
+      self.assertEqual(expected_class, cls)
+      self.assertEqual(name, cls.NAME)
+      self.assertEqual(value, cls.VALUE)
+      self.assertEqual(is_fixed_size, cls.IS_FIXED_SIZE)
 
     self.assertRaises(ValueError, Cell.by_name, 'NOPE')
     self.assertRaises(ValueError, Cell.by_name, 85)
     self.assertRaises(ValueError, Cell.by_name, None)
 
   def test_by_value(self):
-    cls = Cell.by_value(8)
-    self.assertEqual('NETINFO', cls.NAME)
-    self.assertEqual(8, cls.VALUE)
-    self.assertEqual(True, cls.IS_FIXED_SIZE)
+    for (expected_class, name, value, is_fixed_size) in ((NetinfoCell, 'NETINFO', 8, True), (RawRelayCell, 'RELAY', 3, True)):
+      cls = Cell.by_value(value)
+      self.assertEqual(expected_class, cls)
+      self.assertEqual(name, cls.NAME)
+      self.assertEqual(value, cls.VALUE)
+      self.assertEqual(is_fixed_size, cls.IS_FIXED_SIZE)
 
     self.assertRaises(ValueError, Cell.by_value, 'NOPE')
     self.assertRaises(ValueError, Cell.by_value, 85)
@@ -230,7 +235,12 @@ class TestCell(unittest.TestCase):
         self.assertEqual(cell_bytes, RelayCell(circ_id, command, data, digest, stream_id, unused = unused).pack(link_protocol))
         self.assertEqual(cell_bytes, RelayCell(circ_id, command_int, data, digest, stream_id, unused = unused).pack(link_protocol))
 
-      cell = Cell.pop(cell_bytes, link_protocol)[0]
+      # TODO - temporarily, we hack the interim tests by unpacking info via RawRelayCell
+      raw_cell = Cell.pop(cell_bytes, link_protocol)[0]
+      self.assertEqual(circ_id, raw_cell.circ_id)
+      self.assertEqual(cell_bytes[-FIXED_PAYLOAD_LEN:], raw_cell.payload)
+
+      cell = RelayCell._unpack(raw_cell.payload, raw_cell.circ_id, link_protocol)
       self.assertEqual(circ_id, cell.circ_id)
       self.assertEqual(command, cell.command)
       self.assertEqual(command_int, cell.command_int)
@@ -238,7 +248,9 @@ class TestCell(unittest.TestCase):
       self.assertEqual(digest, cell.digest)
       self.assertEqual(stream_id, cell.stream_id)
       self.assertEqual(unused, cell.unused)
+
       self.assertEqual(cell_bytes, cell.pack(link_protocol))
+      self.assertEqual(cell_bytes, raw_cell.pack(link_protocol))
 
     digest = hashlib.sha1(b'hi')
     self.assertEqual(3257622417, RelayCell(5, 'RELAY_BEGIN_DIR', '', digest, 564346860).digest)
@@ -258,7 +270,9 @@ class TestCell(unittest.TestCase):
       ZERO * 498,  # data
     ))
 
-    self.assertRaisesWith(ValueError, 'RELAY cell said it had 65535 bytes of data, but only had 498', Cell.pop, mismatched_data_length_bytes, 2)
+    # TODO - temporarily, we hack the interim tests by unpacking info via RawRelayCell
+    raw_cell = Cell.pop(mismatched_data_length_bytes, 2)[0]
+    self.assertRaisesWith(ValueError, 'RELAY cell said it had 65535 bytes of data, but only had 498', RelayCell._unpack, raw_cell.payload, raw_cell.circ_id, 2)
 
   def test_destroy_cell(self):
     for cell_bytes, (circ_id, reason, reason_int, unused, link_protocol) in DESTROY_CELLS.items():