legacy-email-proxy/tests/test_proxy_server.py

import imaplib
import smtplib

import pytest

from proxy_server import IMAPBackend, SMTPProxyHandler, Settings, env_bool


class DummyIMAP:
    def __init__(self, host, port):
        self.host = host
        self.port = port
        self.logged_in = False
        self.selected = None

    def login(self, username, password):
        self.logged_in = True

    def select(self, mailbox):
        self.selected = mailbox

    def uid(self, command, *args):
        if command == "search":
            return "OK", [b"1 2 3"]
        if command == "fetch" and args[1] == "(RFC822.SIZE)":
            return "OK", [(b"1 (RFC822.SIZE 1024)", b"")]
        if command == "fetch" and args[1] == "(RFC822)":
            return "OK", [b"1 (RFC822 {10}", b"Hello", b" World", b")"]
        return "NO", []

    def logout(self):
        pass

    def expunge(self):
        pass


def test_env_bool_interprets_truthy_values(monkeypatch):
    monkeypatch.setenv("FEATURE_ENABLED", "true")
    assert env_bool("FEATURE_ENABLED") is True
    monkeypatch.setenv("FEATURE_ENABLED", "1")
    assert env_bool("FEATURE_ENABLED") is True
    monkeypatch.setenv("FEATURE_ENABLED", "off")
    assert env_bool("FEATURE_ENABLED") is False
    monkeypatch.delenv("FEATURE_ENABLED", raising=False)
    assert env_bool("FEATURE_ENABLED", default=True) is True


def test_settings_validate_requires_backend_hosts():
    original_imap = Settings.BACKEND_IMAP_HOST
    original_smtp = Settings.BACKEND_SMTP_HOST
    Settings.BACKEND_IMAP_HOST = None
    Settings.BACKEND_SMTP_HOST = None
    with pytest.raises(RuntimeError, match="Missing required environment variables"):
        Settings.validate()
    Settings.BACKEND_IMAP_HOST = original_imap
    Settings.BACKEND_SMTP_HOST = original_smtp


def test_settings_validate_succeeds_with_backends():
    original_imap = Settings.BACKEND_IMAP_HOST
    original_smtp = Settings.BACKEND_SMTP_HOST
    Settings.BACKEND_IMAP_HOST = "imap.example.com"
    Settings.BACKEND_SMTP_HOST = "smtp.example.com"
    Settings.validate()
    Settings.BACKEND_IMAP_HOST = original_imap
    Settings.BACKEND_SMTP_HOST = original_smtp


def test_imap_backend_can_login_and_fetch(monkeypatch):
    monkeypatch.setattr(imaplib, "IMAP4_SSL", lambda host, port: DummyIMAP(host, port))
    backend = IMAPBackend("user", "pass")
    backend.login()
    assert backend.connection.logged_in
    assert backend.connection.selected == "INBOX"
    assert backend.list_uids() == [b"1", b"2", b"3"]
    assert backend.fetch_message_size(b"1") == 1024
    assert b"Hello" in backend.fetch_message(b"1")


def test_smtp_proxy_handler_forwards_message_over_ssl(monkeypatch):
    captured = {}

    class DummySMTP:
        def __init__(self, host, port, timeout=0):
            captured["instance"] = self
            self.host = host
            self.port = port
            self.timeout = timeout
            self.logged_in = False
            self.sent = None

        def login(self, user, password):
            self.logged_in = True

        def sendmail(self, sender, recipients, message):
            self.sent = (sender, recipients, message)

        def quit(self):
            captured["quit"] = True

    monkeypatch.setattr(smtplib, "SMTP_SSL", DummySMTP)
    previous_ssl = Settings.BACKEND_SMTP_USE_SSL
    previous_user = Settings.BACKEND_SMTP_USER
    previous_pass = Settings.BACKEND_SMTP_PASS
    Settings.BACKEND_SMTP_USE_SSL = True
    Settings.BACKEND_SMTP_USER = "smtp-user"
    Settings.BACKEND_SMTP_PASS = "smtp-pass"

    handler = SMTPProxyHandler()
    handler.send_message("from@example.com", ["to@example.com"], b"Subject: Test\r\n\r\nBody\r\n")

    assert captured["instance"].host == Settings.BACKEND_SMTP_HOST
    assert captured["instance"].logged_in is True
    assert captured["instance"].sent[0] == "from@example.com"
    assert captured["instance"].sent[1] == ["to@example.com"]
    assert "Subject: Test" in captured["instance"].sent[2]

    Settings.BACKEND_SMTP_USE_SSL = previous_ssl
    Settings.BACKEND_SMTP_USER = previous_user
    Settings.BACKEND_SMTP_PASS = previous_pass