test: split provider endpoint tests (#4961)

tests/test_provider_endpoints_tailscale.py

@@ -0,0 +1,59 @@
+"""Provider endpoint Tailscale URL-resolution tests.
+
+Covers ``resolve_url``: the hop that rewrites an unresolvable hostname to its
+Tailscale IP. ROADMAP flags plain-HTTP Tailscale URLs as a self-host trap;
+resolve_url is the gate that handles that fallback.
+"""
+import json
+import socket
+import types
+
+import pytest
+
+from src import endpoint_resolver as er
+
+
+# ── resolve_url: Tailscale self-host fallback ──
+# ROADMAP flags plain-HTTP Tailscale URLs as a self-host trap; resolve_url is
+# the hop that rewrites an unresolvable hostname to its Tailscale IP.
+
+class TestResolveUrlTailscale:
+    def setup_method(self):
+        # The module memoizes hostname→IP; clear it so cases don't bleed.
+        er._tailscale_cache.clear()
+
+    def test_dns_success_returns_url_unchanged(self, monkeypatch):
+        monkeypatch.setattr(
+            er.socket, "getaddrinfo",
+            lambda *a, **k: [(2, 1, 6, "", ("1.2.3.4", 0))],
+        )
+        assert er.resolve_url("http://myhost:7000/api") == "http://myhost:7000/api"
+
+    def test_dns_failure_rewrites_to_tailscale_ip(self, monkeypatch):
+        def _fail(*a, **k):
+            raise socket.gaierror("no DNS")
+        monkeypatch.setattr(er.socket, "getaddrinfo", _fail)
+        peers = {"Peer": {"x": {
+            "HostName": "myhost",
+            "DNSName": "myhost.tail.ts.net.",
+            "TailscaleIPs": ["100.64.0.5"],
+        }}}
+        monkeypatch.setattr(
+            er.subprocess, "run",
+            lambda *a, **k: types.SimpleNamespace(returncode=0, stdout=json.dumps(peers)),
+        )
+        # Port is preserved, host swapped for the Tailscale IP.
+        assert er.resolve_url("http://myhost:7000/api") == "http://100.64.0.5:7000/api"
+
+    def test_dns_failure_no_peer_match_keeps_url(self, monkeypatch):
+        def _fail(*a, **k):
+            raise socket.gaierror("no DNS")
+        monkeypatch.setattr(er.socket, "getaddrinfo", _fail)
+        monkeypatch.setattr(
+            er.subprocess, "run",
+            lambda *a, **k: types.SimpleNamespace(returncode=0, stdout=json.dumps({"Peer": {}})),
+        )
+        assert er.resolve_url("http://myhost:7000/api") == "http://myhost:7000/api"
+
+    def test_url_without_hostname_is_returned_as_is(self):
+        assert er.resolve_url("") == ""