Merge pull request #139 from LedgerHQ/fbe/review_from_lucas

Review of the previous PRs

test/python/apps/ethereum.py

@@ -84,7 +84,7 @@ def eth_amount_to_wei(eth_amount: int) -> int:
     return round(eth_amount * 10**18)
 
 def eth_amount_to_wei_hex_string(eth_amount: int) -> str:
-    hex:str = '{:x}'.format(eth_amount_to_wei(eth_amount))
+    hex = '{:x}'.format(eth_amount_to_wei(eth_amount))
     if (len(hex) % 2 != 0):
         hex = "0" + hex
     return hex

test/python/apps/exchange.py

@@ -5,7 +5,8 @@
 from ragger.backend.interface import BackendInterface, RAPDU
 from ragger.utils import prefix_with_len
 
-from ..utils import handle_lib_call_start_or_stop
+from ..utils import handle_lib_call_start_or_stop, int_to_minimally_sized_bytes
+from .exchange_transaction_builder import SubCommand
 
 
 class Command(IntEnum):
@@ -25,12 +26,6 @@ class Rate(IntEnum):
     FLOATING = 0x01
 
 
-class SubCommand(IntEnum):
-    SWAP = 0x00
-    SELL = 0x01
-    FUND = 0x02
-
-
 class Errors(IntEnum):
     INCORRECT_COMMAND_DATA  = 0x6A80
     DESERIALIZATION_FAILED  = 0x6A81
@@ -45,12 +40,6 @@ class Errors(IntEnum):
     SIGN_VERIFICATION_FAIL  = 0x9D1A
 
 
-def _int_to_bytes(n: int) -> bytes:
-    if n == 0:
-        return b'\0'
-    else:
-        return n.to_bytes((n.bit_length() + 7) // 8, 'big')
-
 class ExchangeClient:
     CLA = 0xE0
     def __init__(self,
@@ -100,7 +89,7 @@ def check_partner_key(self, signed_credentials: bytes) -> RAPDU:
         return self._exchange(Command.CHECK_PARTNER, signed_credentials)
 
     def process_transaction(self, transaction: bytes, fees: int) -> RAPDU:
-        fees_bytes = _int_to_bytes(fees)
+        fees_bytes = int_to_minimally_sized_bytes(fees)
         payload = prefix_with_len(transaction) + prefix_with_len(fees_bytes)
         return self._exchange(Command.PROCESS_TRANSACTION_RESPONSE, payload=payload)
 

test/python/apps/exchange_navigation_helper.py

@@ -16,13 +16,10 @@ def _navigate_and_compare(self, accept: bool):
         snapshots_dir_name = self._test_name
         screen_change_after_last_instruction = True
 
-        if self._backend.firmware.device.startswith("nano"):
+        if self._backend.firmware.is_nano:
             navigate_instruction = NavInsID.RIGHT_CLICK
             validation_instructions = [NavInsID.BOTH_CLICK]
-            if accept:
-                text = "Accept"
-            else:
-                text = "Reject"
+            text = "Accept" if accept else "Reject"
         else:
             navigate_instruction = NavInsID.USE_CASE_REVIEW_TAP
             text = "Hold to sign"

test/python/apps/exchange_transaction_builder.py

@@ -1,13 +1,12 @@
 from base64 import urlsafe_b64encode
 from typing import Optional, Dict, Callable, Iterable
-from enum import Enum, auto
+from enum import Enum, auto, IntEnum
 from dataclasses import dataclass
 
 from cryptography.hazmat.primitives.asymmetric import ec
 from cryptography.hazmat.primitives.asymmetric.utils import decode_dss_signature
 
 from .pb.exchange_pb2 import NewFundResponse, NewSellResponse, NewTransactionResponse
-from .exchange import SubCommand
 from .signing_authority import SigningAuthority
 
 class SignatureComputation(Enum):
@@ -26,12 +25,20 @@ class PayloadEncoding(Enum):
     BYTES_ARRAY = auto()
     BASE_64_URL = auto()
 
+
+class SubCommand(IntEnum):
+    SWAP = 0x00
+    SELL = 0x01
+    FUND = 0x02
+
+
 SUBCOMMAND_TO_CURVE = {
     SubCommand.SWAP: ec.SECP256K1(),
     SubCommand.SELL: ec.SECP256R1(),
     SubCommand.FUND: ec.SECP256R1(),
 }
 
+
 def get_partner_curve(sub_command: SubCommand) -> ec.EllipticCurve:
     return SUBCOMMAND_TO_CURVE[sub_command]
 

test/python/utils.py

@@ -7,3 +7,7 @@ def handle_lib_call_start_or_stop(backend):
 
     # The USB stack will be reset by the called app
     backend.handle_usb_reset()
+
+
+def int_to_minimally_sized_bytes(n: int) -> bytes:
+    return n.to_bytes((n.bit_length() + 7) // 8, 'big') or b'\0' # case n is 0