agentic.email/backend/tests/test_mail_sender.py

from types import SimpleNamespace
from unittest.mock import AsyncMock, patch

import pytest

from app.services.mail_sender import build_message, deliver_email, send_via_smtp, sign_message
from app.services.mime_body_extractor import ExtractedMimePart


def test_build_message_formats_named_sender_header():
    message = build_message(
        sender="suyash@gentic.email",
        sender_name="Suyash Dixit",
        recipients=["recipient@example.com"],
        cc=[],
        subject="Named sender",
        body_text="Hello",
        body_html=None,
    )

    assert message["From"] == "Suyash Dixit <suyash@gentic.email>"


def test_build_message_preserves_preformatted_transactional_sender():
    message = build_message(
        sender="aGentic Email <notifications@gentic.email>",
        recipients=["recipient@example.com"],
        cc=[],
        subject="Welcome",
        body_text="Hello",
        body_html=None,
    )

    assert message["From"] == "aGentic Email <notifications@gentic.email>"


def test_build_message_adds_safe_fallback_sender_name():
    message = build_message(
        sender="notifications@gentic.email",
        recipients=["recipient@example.com"],
        cc=[],
        subject="Notification",
        body_text="Hello",
        body_html=None,
    )

    assert message["From"] == "aGentic Email <notifications@gentic.email>"


def test_build_message_includes_file_attachments():
    message = build_message(
        sender="suyash@gentic.email",
        sender_name="Suyash Dixit",
        recipients=["recipient@example.com"],
        cc=[],
        subject="Invoice",
        body_text="See attached",
        body_html="<p>See attached</p>",
        file_attachments=[
            ExtractedMimePart(
                filename="invoice.pdf",
                content_type="application/pdf",
                payload=b"%PDF-1.4",
            )
        ],
    )

    filenames = [
        part.get_filename()
        for part in message.walk()
        if part.get_filename()
    ]
    assert filenames == ["invoice.pdf"]


def test_dkim_sign_uses_selector_before_domain():
    message = build_message(
        sender="user@ritoesis.com",
        recipients=["recipient@example.com"],
        cc=[],
        subject="Test",
        body_text="Hello",
        body_html=None,
    )
    domain = SimpleNamespace(
        domain_name="ritoesis.com",
        dkim_selector="agmail",
        dkim_private_key="private-key",
    )

    with patch(
        "app.services.mail_sender.dkim.sign",
        return_value=b"DKIM-Signature: test\r\n",
    ) as signer:
        sign_message(message, domain)

    assert signer.call_args.args[1] == b"agmail"
    assert signer.call_args.args[2] == b"ritoesis.com"


@pytest.mark.asyncio
async def test_send_via_smtp_uses_configured_client_hostname():
    with patch(
        "app.services.mail_sender.aiosmtplib.send",
        new_callable=AsyncMock,
    ) as send_mock:
        await send_via_smtp(
            b"raw",
            sender="noreply@gentic.email",
            recipients=["user@example.com"],
        )

    assert send_mock.await_args.kwargs["local_hostname"] == "backend.gentic.email"


@pytest.mark.asyncio
async def test_deliver_email_uses_bare_address_for_smtp_envelope():
    domain = SimpleNamespace(
        domain_name="gentic.email",
        dkim_selector="agmail",
        dkim_private_key="private-key",
    )
    with (
        patch(
            "app.services.mail_sender.sign_message",
            return_value=b"signed",
        ),
        patch(
            "app.services.mail_sender.send_via_smtp",
            new_callable=AsyncMock,
        ) as send_mock,
    ):
        await deliver_email(
            sender="notifications@gentic.email",
            sender_name="aGentic Email",
            recipients=["user@example.com"],
            cc=[],
            bcc=[],
            subject="Welcome",
            body_text="Hello",
            body_html=None,
            domain=domain,
        )

    assert send_mock.await_args.kwargs["sender"] == "notifications@gentic.email"


def test_build_message_sets_in_reply_to_and_references():
    message = build_message(
        sender="suyash@gentic.email",
        recipients=["customer@gmail.com"],
        cc=[],
        subject="Re: fresh test",
        body_text="human said B",
        body_html=None,
        in_reply_to="<CAHabc123@mail.gmail.com>",
        references=["<CAHabc123@mail.gmail.com>"],
        message_id="<B@gentic.email>",
    )
    assert message["Message-ID"] == "<B@gentic.email>"
    assert message["In-Reply-To"] == "<CAHabc123@mail.gmail.com>"
    assert message["References"] == "<CAHabc123@mail.gmail.com>"
    raw = message.as_bytes()
    assert b"In-Reply-To: <CAHabc123@mail.gmail.com>" in raw
    assert b"References: <CAHabc123@mail.gmail.com>" in raw


def test_signed_mime_preserves_in_reply_to():
    from unittest.mock import patch

    message = build_message(
        sender="suyash@gentic.email",
        recipients=["customer@gmail.com"],
        cc=[],
        subject="Re: fresh test",
        body_text="human said B",
        body_html=None,
        in_reply_to="<CAHabc123@mail.gmail.com>",
        references=["<CAHabc123@mail.gmail.com>"],
        message_id="<B@gentic.email>",
    )
    domain = SimpleNamespace(
        domain_name="gentic.email",
        dkim_selector="agmail",
        dkim_private_key="private-key",
    )
    with patch(
        "app.services.mail_sender.dkim.sign",
        return_value=b"DKIM-Signature: test\r\n",
    ):
        signed = sign_message(message, domain)
    assert b"In-Reply-To: <CAHabc123@mail.gmail.com>" in signed