feat: add sender/recipient accept gates, security+stress test harnesses, nix flake, and docs

tests/test_smol_to_email.py

@@ -0,0 +1,65 @@
+from types import SimpleNamespace
+
+from pneumatube.smol_to_email import SmolToEmailBridge
+
+
+class _StubSmol:
+    SmolError = RuntimeError
+
+    def cmd_fetch(self, args, store):
+        pass
+
+
+class _StubStore:
+    def __init__(self, rows):
+        self._rows = rows
+        self.requested_box = None
+
+    def mail(self, box):
+        self.requested_box = box
+        return self._rows
+
+
+def _config(**overrides):
+    defaults = {"smolmail_key": "k", "smolmail_db": "d", "require_accepted_sender": True}
+    return SimpleNamespace(**{**defaults, **overrides})
+
+
+def test_poll_once_does_not_stop_after_one_message_fails():
+    """A message that keeps raising out of _relay() (e.g. a value
+    smtp_client.send() rejects that _relay()'s own except clause doesn't
+    cover) must not block every message behind it -- it always sorts first
+    on the next poll, since only a successful _relay() deletes it."""
+    rows = [(b"poison", b"", 0, None), (b"ok", b"", 1, None)]
+    bridge = SmolToEmailBridge(_StubSmol(), _StubStore(rows), account=None, config=_config())
+
+    relayed = []
+
+    def fake_relay(mid, envelope):
+        if mid == b"poison":
+            raise ValueError("simulated failure unrelated to InvalidAddress/OSError")
+        relayed.append(mid)
+
+    bridge._relay = fake_relay
+    bridge.poll_once()
+
+    assert relayed == [b"ok"]
+
+
+def test_poll_once_uses_main_tier_only_by_default():
+    """require_accepted_sender=True (the default) must poll "inbox" (main
+    tier), not "all" -- "all" would include requests-tier mail from
+    first-contact senders with no accept token (SPEC.md S5.8), which is
+    exactly what this setting exists to keep the gateway from relaying."""
+    store = _StubStore([])
+    bridge = SmolToEmailBridge(_StubSmol(), store, account=None, config=_config())
+    bridge.poll_once()
+    assert store.requested_box == "inbox"
+
+
+def test_poll_once_uses_all_tiers_when_open_bridge_enabled():
+    store = _StubStore([])
+    bridge = SmolToEmailBridge(_StubSmol(), store, account=None,
+                                config=_config(require_accepted_sender=False))
+    bridge.poll_once()
+    assert store.requested_box == "all"