diff --git a/tests/unit/test_auth_register_password_reset.py b/tests/unit/test_auth_register_password_reset.py
new file mode 100755
index 000000000..95dcc2cd9
--- /dev/null
+++ b/tests/unit/test_auth_register_password_reset.py
@@ -0,0 +1,705 @@
+"""Auth register + password reset use cases unit tests.
+
+Covers RegisterUserUseCase, VerifyEmailUseCase,
+RequestPasswordResetUseCase, ResetPasswordUseCase.
+"""
+
+from __future__ import annotations
+
+from datetime import datetime, timedelta, timezone
+from unittest.mock import MagicMock
+
+import pytest
+
+from packages.application.auth.password_hasher import password_hasher
+from packages.application.auth.password_reset_use_case import (
+    RequestPasswordResetRequest,
+    RequestPasswordResetUseCase,
+    ResetPasswordRequest,
+    ResetPasswordUseCase,
+)
+from packages.application.auth.register_user_use_case import (
+    RegisterUserRequest,
+    RegisterUserResponse,
+    RegisterUserUseCase,
+    VerifyEmailRequest,
+    VerifyEmailUseCase,
+)
+
+# ── Test helpers ─────────────────────────────────────────
+
+
+class FakeUser:
+    def __init__(self, **kwargs):
+        self.id = kwargs.get("id", "user-123")
+        self.email = kwargs.get("email", "test@example.com")
+        self.display_name = kwargs.get("display_name", "Test User")
+        self.username = kwargs.get("username", "testuser")
+        self.password_hash = kwargs.get("password_hash", "")
+        self.email_verified = kwargs.get("email_verified", False)
+        self.email_verification_token = kwargs.get("email_verification_token", None)
+        self.password_reset_token = kwargs.get("password_reset_token", None)
+        self.password_reset_expires_at = kwargs.get("password_reset_expires_at", None)
+        self.created_at = kwargs.get("created_at", datetime.now(timezone.utc))
+
+
+class FakeUserRepository:
+    def __init__(self, user=None):
+        self._user = user
+        self.saved_user = None
+        self.save_called = 0
+
+    def find_by_email(self, email):
+        if self._user and self._user.email == email:
+            return self._user
+        return None
+
+    def find_by_username(self, username):
+        if self._user and self._user.username == username:
+            return self._user
+        return None
+
+    def find_by_verification_token(self, token):
+        if self._user and self._user.email_verification_token == token:
+            return self._user
+        return None
+
+    def find_by_password_reset_token(self, token):
+        if self._user and self._user.password_reset_token == token:
+            return self._user
+        return None
+
+    def save(self, user):
+        self.saved_user = user
+        self.save_called += 1
+        self._user = user
+        return user
+
+
+class FakeEmailService:
+    def __init__(self, send_success=True, send_error=None):
+        self._send_success = send_success
+        self._send_error = send_error
+        self.sent_emails = []
+        self.verification_emails = []
+        self.password_reset_emails = []
+
+    def send_verification_email(self, to_email, username, verification_url):
+        self.verification_emails.append(
+            {
+                "to": to_email,
+                "username": username,
+                "url": verification_url,
+            }
+        )
+        self.sent_emails.append(("verification", to_email))
+        return self._send_success, self._send_error
+
+    def send_password_reset_email(self, to_email, username, reset_url):
+        self.password_reset_emails.append(
+            {
+                "to": to_email,
+                "username": username,
+                "url": reset_url,
+            }
+        )
+        self.sent_emails.append(("password_reset", to_email))
+        return self._send_success, self._send_error
+
+
+class FailingEmailService:
+    """Email service that raises an exception."""
+
+    def send_verification_email(self, **kwargs):
+        raise RuntimeError("SMTP connection failed")
+
+    def send_password_reset_email(self, **kwargs):
+        raise RuntimeError("SMTP connection failed")
+
+
+# ── RegisterUserUseCase tests ───────────────────────────
+
+
+class TestRegisterUserUseCase:
+    def _make_use_case(self, repo=None, email_service=None):
+        return RegisterUserUseCase(
+            user_repository=repo or FakeUserRepository(),
+            base_url="https://app.example.com",
+            email_service=email_service or FakeEmailService(),
+        )
+
+    def test_successful_registration(self):
+        repo = FakeUserRepository()
+        email_svc = FakeEmailService()
+        use_case = self._make_use_case(repo=repo, email_service=email_svc)
+
+        req = RegisterUserRequest(
+            email="newuser@example.com",
+            password="StrongPass123!",
+            username="newuser",
+            display_name="New User",
+        )
+        response, error = use_case.execute(req)
+
+        assert error is None
+        assert response is not None
+        assert isinstance(response, RegisterUserResponse)
+        assert response.email == "newuser@example.com"
+        assert response.username == "newuser"
+        assert response.display_name == "New User"
+        assert response.user_id
+        assert response.email_verification_sent is True
+
+        # user was saved
+        assert repo.saved_user is not None
+        assert repo.saved_user.email == "newuser@example.com"
+        assert repo.saved_user.email_verified is False
+        assert repo.saved_user.email_verification_token is not None
+        # password was hashed
+        assert repo.saved_user.password_hash != "StrongPass123!"
+        assert password_hasher.verify_password("StrongPass123!", repo.saved_user.password_hash)
+
+        # email was sent
+        assert len(email_svc.verification_emails) == 1
+        sent = email_svc.verification_emails[0]
+        assert sent["to"] == "newuser@example.com"
+        assert sent["username"] == "newuser"
+        assert "verify-email?token=" in sent["url"]
+        assert "https://app.example.com" in sent["url"]
+
+    def test_email_stripped_and_lowercased(self):
+        repo = FakeUserRepository()
+        use_case = self._make_use_case(repo=repo)
+
+        req = RegisterUserRequest(
+            email="  NEWUSER@EXAMPLE.COM  ",
+            password="StrongPass123!",
+            username="newuser",
+            display_name="New User",
+        )
+        response, error = use_case.execute(req)
+
+        assert error is None
+        assert response is not None
+        assert response.email == "newuser@example.com"
+        assert repo.saved_user.email == "newuser@example.com"
+
+    def test_username_stripped(self):
+        repo = FakeUserRepository()
+        use_case = self._make_use_case(repo=repo)
+
+        req = RegisterUserRequest(
+            email="a@b.com",
+            password="StrongPass123!",
+            username="  myuser  ",
+            display_name="Display",
+        )
+        response, error = use_case.execute(req)
+
+        assert error is None
+        assert response.username == "myuser"
+
+    def test_display_name_stripped(self):
+        repo = FakeUserRepository()
+        use_case = self._make_use_case(repo=repo)
+
+        req = RegisterUserRequest(
+            email="a@b.com",
+            password="StrongPass123!",
+            username="user",
+            display_name="  My Name  ",
+        )
+        response, error = use_case.execute(req)
+
+        assert error is None
+        assert response.display_name == "My Name"
+
+    def test_empty_email_returns_error(self):
+        use_case = self._make_use_case()
+        req = RegisterUserRequest(email="", password="StrongPass123!", username="u", display_name="D")
+        response, error = use_case.execute(req)
+
+        assert response is None
+        assert "Email is required" in error
+
+    def test_empty_username_returns_error(self):
+        use_case = self._make_use_case()
+        req = RegisterUserRequest(email="a@b.com", password="StrongPass123!", username="  ", display_name="D")
+        response, error = use_case.execute(req)
+
+        assert response is None
+        assert "Username is required" in error
+
+    def test_empty_display_name_returns_error(self):
+        use_case = self._make_use_case()
+        req = RegisterUserRequest(email="a@b.com", password="StrongPass123!", username="u", display_name="  ")
+        response, error = use_case.execute(req)
+
+        assert response is None
+        assert "Display name is required" in error
+
+    def test_weak_password_returns_error(self):
+        use_case = self._make_use_case()
+        req = RegisterUserRequest(email="a@b.com", password="weak", username="u", display_name="D")
+        response, error = use_case.execute(req)
+
+        assert response is None
+        assert error is not None
+        # password validation error message
+        assert len(error) > 0
+
+    def test_email_already_registered(self):
+        existing = FakeUser(email="existing@example.com", username="existinguser")
+        repo = FakeUserRepository(user=existing)
+        use_case = self._make_use_case(repo=repo)
+
+        req = RegisterUserRequest(
+            email="existing@example.com",
+            password="StrongPass123!",
+            username="newuser",
+            display_name="New User",
+        )
+        response, error = use_case.execute(req)
+
+        assert response is None
+        assert "Email already registered" in error
+        # no new user saved
+        assert repo.save_called == 0
+
+    def test_username_already_taken(self):
+        existing = FakeUser(email="other@example.com", username="taken")
+        repo = FakeUserRepository(user=existing)
+        use_case = self._make_use_case(repo=repo)
+
+        req = RegisterUserRequest(
+            email="new@example.com",
+            password="StrongPass123!",
+            username="taken",
+            display_name="New User",
+        )
+        response, error = use_case.execute(req)
+
+        assert response is None
+        assert "Username already taken" in error
+
+    def test_email_service_failure_user_still_created(self):
+        repo = FakeUserRepository()
+        email_svc = FakeEmailService(send_success=False, send_error="SMTP error")
+        use_case = self._make_use_case(repo=repo, email_service=email_svc)
+
+        req = RegisterUserRequest(
+            email="a@b.com",
+            password="StrongPass123!",
+            username="user",
+            display_name="User",
+        )
+        response, error = use_case.execute(req)
+
+        # user still created
+        assert error is None
+        assert response is not None
+        assert response.email_verification_sent is False
+        assert repo.saved_user is not None
+
+    def test_email_service_exception_user_still_created(self):
+        repo = FakeUserRepository()
+        use_case = RegisterUserUseCase(
+            user_repository=repo,
+            base_url="https://app.example.com",
+            email_service=FailingEmailService(),
+        )
+
+        req = RegisterUserRequest(
+            email="a@b.com",
+            password="StrongPass123!",
+            username="user",
+            display_name="User",
+        )
+        response, error = use_case.execute(req)
+
+        assert error is None
+        assert response is not None
+        assert response.email_verification_sent is False
+        assert repo.saved_user is not None
+
+    def test_exception_handling(self):
+        repo = MagicMock()
+        repo.find_by_email.side_effect = RuntimeError("DB down")
+        use_case = self._make_use_case(repo=repo)
+
+        req = RegisterUserRequest(
+            email="a@b.com",
+            password="StrongPass123!",
+            username="user",
+            display_name="User",
+        )
+        response, error = use_case.execute(req)
+
+        assert response is None
+        assert "Registration failed" in error
+
+    def test_user_id_is_generated(self):
+        repo = FakeUserRepository()
+        use_case = self._make_use_case(repo=repo)
+
+        req = RegisterUserRequest(email="a@b.com", password="StrongPass123!", username="u", display_name="D")
+        response, _ = use_case.execute(req)
+
+        assert response.user_id
+        assert len(response.user_id) == 32  # uuid4 hex
+
+
+# ── VerifyEmailUseCase tests ────────────────────────────
+
+
+class TestVerifyEmailUseCase:
+    def test_successful_verification(self):
+        user = FakeUser(email_verified=False, email_verification_token="test-token-123")
+        repo = FakeUserRepository(user=user)
+        use_case = VerifyEmailUseCase(user_repository=repo)
+
+        req = VerifyEmailRequest(token="test-token-123")
+        success, error = use_case.execute(req)
+
+        assert success is True
+        assert error is None
+        assert repo.saved_user.email_verified is True
+        assert repo.saved_user.email_verification_token is None
+
+    def test_empty_token(self):
+        repo = FakeUserRepository()
+        use_case = VerifyEmailUseCase(user_repository=repo)
+
+        req = VerifyEmailRequest(token="")
+        success, error = use_case.execute(req)
+
+        assert success is False
+        assert "Verification token is required" in error
+
+    def test_invalid_token(self):
+        repo = FakeUserRepository()
+        use_case = VerifyEmailUseCase(user_repository=repo)
+
+        req = VerifyEmailRequest(token="nonexistent-token")
+        success, error = use_case.execute(req)
+
+        assert success is False
+        assert "Invalid or expired verification token" in error
+
+    def test_already_verified_returns_success(self):
+        user = FakeUser(email_verified=True, email_verification_token="some-token")
+        repo = FakeUserRepository(user=user)
+        use_case = VerifyEmailUseCase(user_repository=repo)
+
+        req = VerifyEmailRequest(token="some-token")
+        success, error = use_case.execute(req)
+
+        assert success is True
+        assert error is None
+        # idempotent - no save needed
+        # (depends on implementation - current returns early without save)
+
+    def test_token_cleared_after_verification(self):
+        user = FakeUser(email_verified=False, email_verification_token="tok123")
+        repo = FakeUserRepository(user=user)
+        use_case = VerifyEmailUseCase(user_repository=repo)
+
+        req = VerifyEmailRequest(token="tok123")
+        use_case.execute(req)
+
+        assert repo.saved_user.email_verification_token is None
+
+    def test_exception_handling(self):
+        repo = MagicMock()
+        repo.find_by_verification_token.side_effect = RuntimeError("DB down")
+        use_case = VerifyEmailUseCase(user_repository=repo)
+
+        req = VerifyEmailRequest(token="token")
+        success, error = use_case.execute(req)
+
+        assert success is False
+        assert "Email verification failed" in error
+
+
+# ── RequestPasswordResetUseCase tests ───────────────────
+
+
+class TestRequestPasswordResetUseCase:
+    def _make_use_case(self, repo=None, email_service=None, expire_hours=1):
+        return RequestPasswordResetUseCase(
+            user_repository=repo or FakeUserRepository(),
+            base_url="https://app.example.com",
+            token_expire_hours=expire_hours,
+            email_service=email_service or FakeEmailService(),
+        )
+
+    def test_successful_request(self):
+        user = FakeUser(email="user@example.com", username="testuser")
+        repo = FakeUserRepository(user=user)
+        email_svc = FakeEmailService()
+        use_case = self._make_use_case(repo=repo, email_service=email_svc)
+
+        req = RequestPasswordResetRequest(email="user@example.com")
+        success, error = use_case.execute(req)
+
+        assert success is True
+        assert error is None
+
+        # token set on user
+        assert repo.saved_user.password_reset_token is not None
+        assert len(repo.saved_user.password_reset_token) > 10
+        assert repo.saved_user.password_reset_expires_at is not None
+
+        # email sent
+        assert len(email_svc.password_reset_emails) == 1
+        sent = email_svc.password_reset_emails[0]
+        assert sent["to"] == "user@example.com"
+        assert "reset-password?token=" in sent["url"]
+
+    def test_empty_email(self):
+        use_case = self._make_use_case()
+        req = RequestPasswordResetRequest(email="")
+        success, error = use_case.execute(req)
+
+        assert success is False
+        assert "Email is required" in error
+
+    def test_nonexistent_user_returns_true_security(self):
+        repo = FakeUserRepository()  # no users
+        use_case = self._make_use_case(repo=repo)
+
+        req = RequestPasswordResetRequest(email="nobody@example.com")
+        success, error = use_case.execute(req)
+
+        # Always returns true to prevent user enumeration
+        assert success is True
+        assert error is None
+        assert repo.save_called == 0  # no save
+
+    def test_token_expiry_set_correctly(self):
+        user = FakeUser(email="u@e.com")
+        repo = FakeUserRepository(user=user)
+        use_case = self._make_use_case(repo=repo, expire_hours=2)
+
+        before = datetime.now(timezone.utc)
+        req = RequestPasswordResetRequest(email="u@e.com")
+        use_case.execute(req)
+        after = datetime.now(timezone.utc)
+
+        expires_at = repo.saved_user.password_reset_expires_at
+        assert expires_at is not None
+        # should be ~2 hours from now
+        min_expected = before + timedelta(hours=2)
+        max_expected = after + timedelta(hours=2)
+        assert min_expected <= expires_at <= max_expected + timedelta(seconds=1)
+
+    def test_default_expire_hours(self):
+        user = FakeUser(email="u@e.com")
+        repo = FakeUserRepository(user=user)
+        use_case = RequestPasswordResetUseCase(
+            user_repository=repo,
+            base_url="https://app.example.com",
+            email_service=FakeEmailService(),
+        )
+
+        before = datetime.now(timezone.utc)
+        req = RequestPasswordResetRequest(email="u@e.com")
+        use_case.execute(req)
+
+        expires_at = repo.saved_user.password_reset_expires_at
+        assert expires_at is not None
+        # default is 1 hour
+        assert timedelta(minutes=55) < (expires_at - before) < timedelta(hours=1, minutes=1)
+
+    def test_email_service_failure_still_returns_true(self):
+        user = FakeUser(email="u@e.com")
+        repo = FakeUserRepository(user=user)
+        email_svc = FakeEmailService(send_success=False, send_error="SMTP down")
+        use_case = self._make_use_case(repo=repo, email_service=email_svc)
+
+        req = RequestPasswordResetRequest(email="u@e.com")
+        success, error = use_case.execute(req)
+
+        # still returns true for security
+        assert success is True
+        assert error is None
+        # token still set
+        assert repo.saved_user.password_reset_token is not None
+
+    def test_email_service_exception_still_returns_true(self):
+        user = FakeUser(email="u@e.com")
+        repo = FakeUserRepository(user=user)
+        use_case = RequestPasswordResetUseCase(
+            user_repository=repo,
+            base_url="https://app.example.com",
+            email_service=FailingEmailService(),
+        )
+
+        req = RequestPasswordResetRequest(email="u@e.com")
+        success, error = use_case.execute(req)
+
+        assert success is True
+        assert error is None
+        assert repo.saved_user.password_reset_token is not None
+
+    def test_email_stripped_lowercased(self):
+        user = FakeUser(email="u@e.com")
+        repo = FakeUserRepository(user=user)
+        use_case = self._make_use_case(repo=repo)
+
+        req = RequestPasswordResetRequest(email="  U@E.COM  ")
+        # email would be normalized but find_by_email should still find it
+        # since our fake repo compares exact strings
+        # Let's just check the normalization happens
+        assert req.email == "u@e.com"
+
+    def test_exception_handling(self):
+        repo = MagicMock()
+        repo.find_by_email.side_effect = RuntimeError("DB down")
+        use_case = self._make_use_case(repo=repo)
+
+        req = RequestPasswordResetRequest(email="a@b.com")
+        success, error = use_case.execute(req)
+
+        assert success is False
+        assert "Password reset request failed" in error
+
+
+# ── ResetPasswordUseCase tests ──────────────────────────
+
+
+class TestResetPasswordUseCase:
+    def test_successful_reset(self):
+        token = "reset-token-123"
+        old_hash = password_hasher.hash_password("oldpassword")
+        user = FakeUser(
+            password_hash=old_hash,
+            password_reset_token=token,
+            password_reset_expires_at=datetime.now(timezone.utc) + timedelta(hours=1),
+        )
+        repo = FakeUserRepository(user=user)
+        use_case = ResetPasswordUseCase(user_repository=repo)
+
+        req = ResetPasswordRequest(token=token, new_password="NewStrongPass456!")
+        success, error = use_case.execute(req)
+
+        assert success is True
+        assert error is None
+
+        # password updated
+        assert repo.saved_user.password_hash != old_hash
+        assert password_hasher.verify_password("NewStrongPass456!", repo.saved_user.password_hash)
+
+        # token cleared
+        assert repo.saved_user.password_reset_token is None
+        assert repo.saved_user.password_reset_expires_at is None
+
+    def test_empty_token(self):
+        use_case = ResetPasswordUseCase(user_repository=FakeUserRepository())
+        req = ResetPasswordRequest(token="", new_password="StrongPass123!")
+        success, error = use_case.execute(req)
+
+        assert success is False
+        assert "Reset token is required" in error
+
+    def test_empty_new_password(self):
+        use_case = ResetPasswordUseCase(user_repository=FakeUserRepository())
+        req = ResetPasswordRequest(token="token", new_password="")
+        success, error = use_case.execute(req)
+
+        assert success is False
+        assert "New password is required" in error
+
+    def test_weak_new_password(self):
+        use_case = ResetPasswordUseCase(user_repository=FakeUserRepository())
+        req = ResetPasswordRequest(token="token", new_password="weak")
+        success, error = use_case.execute(req)
+
+        assert success is False
+        assert error is not None
+        # some validation error
+        assert len(error) > 0
+
+    def test_invalid_token(self):
+        repo = FakeUserRepository()  # no user with this token
+        use_case = ResetPasswordUseCase(user_repository=repo)
+
+        req = ResetPasswordRequest(token="bad-token", new_password="StrongPass123!")
+        success, error = use_case.execute(req)
+
+        assert success is False
+        assert "Invalid or expired reset token" in error
+
+    def test_expired_token(self):
+        token = "expired-token"
+        user = FakeUser(
+            password_reset_token=token,
+            password_reset_expires_at=datetime.now(timezone.utc) - timedelta(hours=1),
+        )
+        repo = FakeUserRepository(user=user)
+        use_case = ResetPasswordUseCase(user_repository=repo)
+
+        req = ResetPasswordRequest(token=token, new_password="StrongPass123!")
+        success, error = use_case.execute(req)
+
+        assert success is False
+        assert "expired" in error.lower()
+
+    def test_naive_datetime_expiry_treated_as_utc(self):
+        token = "naive-token"
+        # naive datetime representing UTC time 1 hour in the past
+        naive_expired = datetime.now(timezone.utc).replace(tzinfo=None) - timedelta(hours=1)
+        user = FakeUser(
+            password_reset_token=token,
+            password_reset_expires_at=naive_expired,
+        )
+        repo = FakeUserRepository(user=user)
+        use_case = ResetPasswordUseCase(user_repository=repo)
+
+        req = ResetPasswordRequest(token=token, new_password="StrongPass123!")
+        success, error = use_case.execute(req)
+
+        assert success is False
+        assert "expired" in error.lower()
+
+    def test_no_expiry_set_does_not_expire(self):
+        token = "no-expiry-token"
+        user = FakeUser(
+            password_reset_token=token,
+            password_reset_expires_at=None,
+        )
+        repo = FakeUserRepository(user=user)
+        use_case = ResetPasswordUseCase(user_repository=repo)
+
+        req = ResetPasswordRequest(token=token, new_password="StrongPass123!")
+        success, error = use_case.execute(req)
+
+        # no expiry = should work
+        assert success is True
+        assert error is None
+
+    def test_token_cleared_after_reset(self):
+        token = "clear-me"
+        user = FakeUser(
+            password_reset_token=token,
+            password_reset_expires_at=datetime.now(timezone.utc) + timedelta(hours=1),
+        )
+        repo = FakeUserRepository(user=user)
+        use_case = ResetPasswordUseCase(user_repository=repo)
+
+        req = ResetPasswordRequest(token=token, new_password="StrongPass123!")
+        use_case.execute(req)
+
+        assert repo.saved_user.password_reset_token is None
+        assert repo.saved_user.password_reset_expires_at is None
+
+    def test_exception_handling(self):
+        repo = MagicMock()
+        repo.find_by_password_reset_token.side_effect = RuntimeError("DB down")
+        use_case = ResetPasswordUseCase(user_repository=repo)
+
+        req = ResetPasswordRequest(token="token", new_password="StrongPass123!")
+        success, error = use_case.execute(req)
+
+        assert success is False
+        assert "Password reset failed" in error