More tests; minor reformatting

src/seedsigner/models/seed.py

@@ -42,7 +42,7 @@ class Seed:
             raise Exception(f"Unrecognized wordlist_language_code {wordlist_language_code}")
 
 
-    def _generate_seed(self) -> bool:
+    def _generate_seed(self):
         try:
             self.seed_bytes = bip39.mnemonic_to_seed(self.mnemonic_str, password=self._passphrase, wordlist=self.wordlist)
         except Exception as e:
@@ -64,6 +64,7 @@ class Seed:
     def wordlist_language_code(self) -> str:
         return self._wordlist_language_code
 
+
     @property
     def mnemonic_display_str(self) -> str:
         return unicodedata.normalize("NFC", " ".join(self._mnemonic))
@@ -106,29 +107,36 @@ class Seed:
         # TODO: Support other BIP-39 wordlist languages!
         raise Exception("Not yet implemented!")
 
+
     @property
     def script_override(self) -> list:
         return None
-    
+
+
     def derivation_override(self, wallet_type: str  = SettingsConstants.SINGLE_SIG) -> str:
         return None
 
+
     def detect_version(self, derivation_path: str, network: str = SettingsConstants.MAINNET, wallet_type: str = SettingsConstants.SINGLE_SIG) -> str:
         embit_network = NETWORKS[SettingsConstants.map_network_to_embit(network)]
         return bip32.detect_version(derivation_path, default="xpub", network=embit_network)
 
+
     @property
     def passphrase_label(self) -> str:
         return SettingsConstants.LABEL__BIP39_PASSPHRASE
 
+
     @property
     def seedqr_supported(self) -> bool:
         return True
 
+
     @property
     def bip85_supported(self) -> bool:
         return True
 
+
     def get_fingerprint(self, network: str = SettingsConstants.MAINNET) -> str:
         root = bip32.HDKey.from_seed(self.seed_bytes, version=NETWORKS[SettingsConstants.map_network_to_embit(network)]["xprv"])
         return hexlify(root.child(0).fingerprint).decode('utf-8')
@@ -158,19 +166,20 @@ class Seed:
 
 class ElectrumSeed(Seed):
 
-
-    def _generate_seed(self) -> bool:
+    def _generate_seed(self):
         if len(self._mnemonic) != 12:
-            return False
+            raise InvalidSeedException(f"Unsupported Electrum seed length: {len(self._mnemonic)}")
+
         s = hmac.digest(b"Seed version", self.mnemonic_str.encode('utf8'), hashlib.sha512).hex()
         prefix = s[0:3]
+
         # only support Electrum Segwit version for now
         if SettingsConstants.ELECTRUM_SEED_SEGWIT == prefix:
             self.seed_bytes=hashlib.pbkdf2_hmac('sha512', self.mnemonic_str.encode('utf-8'), b'electrum' + self._passphrase.encode('utf-8'), iterations = SettingsConstants.ELECTRUM_PBKDF2_ROUNDS)
-            return True
+
         else:
-            raise InvalidSeedException("Unsupported electrum seed input")
-            return False
+            raise InvalidSeedException(f"Unsupported Electrum seed format: {prefix}")
+
 
     def set_passphrase(self, passphrase: str, regenerate_seed: bool = True):
         if passphrase:
@@ -184,6 +193,7 @@ class ElectrumSeed(Seed):
             # Regenerate the internal seed since passphrase changes the result
             self._generate_seed()
 
+
     @staticmethod
     def normalize_electrum_passphrase(passphrase : str) -> str:
         passphrase = unicodedata.normalize('NFKD', passphrase)
@@ -193,25 +203,31 @@ class ElectrumSeed(Seed):
         passphrase = u' '.join(passphrase.split())
         return passphrase
 
+
     @property
     def script_override(self) -> list:
             return [SettingsConstants.NATIVE_SEGWIT]
 
+
     def derivation_override(self, wallet_type: str = SettingsConstants.SINGLE_SIG) -> str:
         return "m/0h" if SettingsConstants.SINGLE_SIG == wallet_type else "m/1h"
 
+
     def detect_version(self, derivation_path: str, network: str = SettingsConstants.MAINNET, wallet_type: str = SettingsConstants.SINGLE_SIG) -> str:
         embit_network = NETWORKS[SettingsConstants.map_network_to_embit(network)]
         return embit_network["zpub"] if SettingsConstants.SINGLE_SIG == wallet_type else embit_network["Zpub"]
 
+
     @property
     def passphrase_label(self) -> str:
         return SettingsConstants.LABEL__CUSTOM_EXTENSION
 
+
     @property
     def seedqr_supported(self) -> bool:
         return False
 
+
     @property
     def bip85_supported(self) -> bool:
         return False

src/seedsigner/models/settings_definition.py

@@ -209,6 +209,8 @@ class SettingsConstants:
     LABEL__BIP39_PASSPHRASE = "BIP-39 Passphrase"
     LABEL__CUSTOM_EXTENSION = "Custom Extension"
 
+
+
 @dataclass
 class SettingsEntry:
     """

src/seedsigner/views/seed_views.py

@@ -620,6 +620,7 @@ class SeedBackupView(View):
 
     def run(self):
         button_data = [self.VIEW_WORDS]
+
         if self.seed.seedqr_supported:
             button_data.append(self.EXPORT_SEEDQR)
 

tests/test_flows_seed.py

@@ -152,6 +152,7 @@ class TestSeedFlows(FlowTest):
                 ]
 
             else:
+                # Or we bomb out if the mnemonic is invalid for Electrum
                 sequence.append(FlowStep(seed_views.SeedMnemonicInvalidView, button_data_selection=seed_views.SeedMnemonicInvalidView.DISCARD))
 
             self.run_sequence(sequence)
@@ -164,10 +165,8 @@ class TestSeedFlows(FlowTest):
         test_with_mnemonic("morning pretty hobby click extend color wait joke define sausage boost salmon".split())
         test_with_mnemonic("basket print toy noodle betray weird filter ticket insect copy force machine".split())
 
-        # Most BIP-39 seeds should fail; test seeds generated by bitcoiner.guide
+        # Most BIP-39 seeds should fail; test seed generated by bitcoiner.guide
         test_with_mnemonic("pioneer divide volcano art victory family grow novel mandate bicycle senior adjust".split(), expects_electrum_seed_is_valid=False)
-        test_with_mnemonic("gentle combine cool hamster ghost harvest gossip lend dismiss slam any toast".split(), expects_electrum_seed_is_valid=False)
-        test_with_mnemonic("enough board blossom stamp fire buffalo digital solution sadness random number stone".split(), expects_electrum_seed_is_valid=False)
 
 
     def test_export_xpub_standard_flow(self):

tests/test_seed.py

@@ -1,8 +1,10 @@
-from seedsigner.models.seed import Seed, ElectrumSeed
+import pytest
+from seedsigner.models.seed import InvalidSeedException, Seed, ElectrumSeed
 
 from seedsigner.models.settings import SettingsConstants
 
 
+# TODO: Change TAB indents to SPACE
 
 def test_seed():
 	seed = Seed(mnemonic="obscure bone gas open exotic abuse virus bunker shuffle nasty ship dash".split())
@@ -37,9 +39,47 @@ def test_seed():
 
 	
 def test_electrum_seed():
+	"""
+	ElectrumSeed should correctly parse a modern Electrum mnemonic.
+	"""
 	seed = ElectrumSeed(mnemonic="regular reject rare profit once math fringe chase until ketchup century escape".split())
 
 	intended_seed = b'\xcan|\xf8\x8a\x8d\xf78=Pq\xc4_\xe6\x02\x91\xfcs\xb2[\xed*\xdc\xc7%\xb6[_-(~D\xe5\x1e\x85%N\x9c\x03\x9dh\xafX}\x16\xb1\x99,\xbe\xc4\x11\xfaW\x0f\xb0\x89yD\xf4\x0f\xd5?\x8eA'
 
 	assert seed.seed_bytes == intended_seed
 
+
+def test_electrum_mnemonic_format():
+	"""
+	ElectrumSeed should reject mnemonics that are not 12 words long.
+	"""
+	with pytest.raises(InvalidSeedException):
+		ElectrumSeed(mnemonic=["regular"] * 11)
+
+	with pytest.raises(InvalidSeedException):
+		ElectrumSeed(mnemonic=["regular"] * 13)
+
+	with pytest.raises(InvalidSeedException):
+		ElectrumSeed(mnemonic=["regular"] * 24)
+
+
+def test_electrum_seed_rejects_most_bip39_mnemonics():
+	"""
+	ElectrumSeed should throw an exception for most BIP-39 mnemonics.
+
+	There are 1/16 odds that a seed will be valid for both formats.
+	"""
+	# Most BIP-39 seeds should fail; test seeds generated by bitcoiner.guide
+	with pytest.raises(InvalidSeedException):
+		ElectrumSeed(mnemonic="pioneer divide volcano art victory family grow novel mandate bicycle senior adjust".split())
+
+	with pytest.raises(InvalidSeedException):
+		ElectrumSeed(mnemonic="gentle combine cool hamster ghost harvest gossip lend dismiss slam any toast".split())
+
+	with pytest.raises(InvalidSeedException):
+		ElectrumSeed(mnemonic="enough board blossom stamp fire buffalo digital solution sadness random number stone".split())
+
+	# This one is valid for both formats
+	mnemonic = "only gain spot output unknown craft simple cram absorb suggest ridge famous".split()
+	Seed(mnemonic)
+	ElectrumSeed(mnemonic)