Add selective Postfix SRS installation and management

tests/test_srs_dns.py

@@ -0,0 +1,106 @@
+#!/usr/bin/env python3
+"""Offline regression tests for the selective SRS DNS preflight helper.
+
+All DNS responses are mocked. No live DNS queries, Postfix changes,
+or SRS installation operations are performed.
+"""
+
+import contextlib
+import io
+import runpy
+import unittest
+from pathlib import Path
+from unittest.mock import patch
+
+
+ROOT = Path(__file__).resolve().parents[1]
+HELPER = ROOT / "helpers/srs-dns-check.py"
+
+module = runpy.run_path(str(HELPER))
+check_server = module["check_server"]
+
+
+class TestSrsDnsSpf(unittest.TestCase):
+
+    DOMAIN = "srs.example.org"
+    HOSTNAME = "mail.example.org"
+    IPV4 = "192.0.2.25"
+    IPV6 = "2001:db8::25"
+
+    def check_with_spf(self, txt_records):
+        answers = {
+            (self.DOMAIN, "TXT"): txt_records,
+            (self.DOMAIN, "MX"): [
+                f"10 {self.HOSTNAME}."
+            ],
+            (self.HOSTNAME, "A"): [
+                self.IPV4
+            ],
+            (self.HOSTNAME, "AAAA"): [
+                self.IPV6
+            ],
+        }
+
+        def fake_dig(server, name, kind, authoritative=False):
+            self.assertEqual(server, "192.0.2.53")
+            self.assertTrue(
+                authoritative,
+                "DNS checks must query authoritative nameservers"
+            )
+            return answers.get((name, kind), [])
+
+        output = io.StringIO()
+
+        with patch.dict(
+            check_server.__globals__,
+            {"dig": fake_dig}
+        ):
+            with contextlib.redirect_stdout(output):
+                result = check_server(
+                    "ns.example.org",
+                    "192.0.2.53",
+                    self.DOMAIN,
+                    self.HOSTNAME,
+                    self.IPV4,
+                    self.IPV6,
+                )
+
+        return result, output.getvalue()
+
+    def test_valid_spf(self):
+        result, output = self.check_with_spf(
+            ['"v=spf1 mx -all"']
+        )
+
+        self.assertEqual(result, (True, True))
+        self.assertIn("[ ok ]", output)
+
+    def test_missing_spf(self):
+        result, output = self.check_with_spf([])
+
+        self.assertEqual(result, (False, False))
+        self.assertIn("SPF is not the approved", output)
+        self.assertIn("[ failed ]", output)
+
+    def test_invalid_spf(self):
+        result, output = self.check_with_spf(
+            ['"v=spf1 -all"']
+        )
+
+        self.assertEqual(result, (False, False))
+        self.assertIn("SPF is not the approved", output)
+        self.assertIn("[ failed ]", output)
+
+    def test_multiple_spf_records(self):
+        result, output = self.check_with_spf([
+            '"v=spf1 mx -all"',
+            '"v=spf1 ip4:192.0.2.1 -all"',
+        ])
+
+        self.assertEqual(result, (False, False))
+        self.assertIn("SPF is not the approved", output)
+        self.assertIn("[ failed ]", output)
+
+
+if __name__ == "__main__":
+    unittest.main(verbosity=2)