Add security tooling and password length test

src/tests/test_password_length_constraints.py

@@ -0,0 +1,31 @@
+import pytest
+from pathlib import Path
+import sys
+
+sys.path.append(str(Path(__file__).resolve().parents[1]))
+
+from password_manager.password_generation import PasswordGenerator
+from constants import MIN_PASSWORD_LENGTH
+
+
+class DummyEnc:
+    def derive_seed_from_mnemonic(self, mnemonic):
+        return b"\x00" * 32
+
+
+class DummyBIP85:
+    def derive_entropy(self, index: int, bytes_len: int, app_no: int = 32) -> bytes:
+        return bytes((index + i) % 256 for i in range(bytes_len))
+
+
+def make_generator():
+    pg = PasswordGenerator.__new__(PasswordGenerator)
+    pg.encryption_manager = DummyEnc()
+    pg.bip85 = DummyBIP85()
+    return pg
+
+
+def test_generate_password_too_short_raises():
+    pg = make_generator()
+    with pytest.raises(ValueError):
+        pg.generate_password(length=MIN_PASSWORD_LENGTH - 1)