Improve dns responses parsing

cmdeploy/src/cmdeploy/remote/rdns.py

@@ -73,9 +73,7 @@ def query_dns(typ, domain):
 
     # Query authoritative nameserver directly to bypass DNS cache.
     res = shell(f"dig @{ns} -r -q {domain} -t {typ} +short", print=log_progress)
-    if res:
-        return res.split("\n")[0]
-    return ""
+    return next((line for line in res.split("\n") if not line.startswith(';')), '')
 
 
 def check_zonefile(zonefile, verbose=True):

cmdeploy/src/cmdeploy/tests/test_dns.py

@@ -1,3 +1,5 @@
+from copy import deepcopy
+
 import pytest
 
 from cmdeploy import remote
@@ -8,38 +10,63 @@
 def mockdns_base(monkeypatch):
     qdict = {}
 
-    def query_dns(typ, domain):
-        try:
-            return qdict[typ][domain]
-        except KeyError:
-            return ""
-
-    monkeypatch.setattr(remote.rdns, query_dns.__name__, query_dns)
+    def shell(command, fail_ok=False, print=print):
+        if command.startswith("dig"):
+            if command == "dig":
+                return "."
+            if "SOA" in command:
+                return (
+                    "delta.chat. 21600 IN SOA ns1.first-ns.de. dns.hetzner.com."
+                    " 2025102800 14400 1800 604800 3600"
+                )
+            command_chunks = command.split()
+            domain, typ = command_chunks[4], command_chunks[6]
+            try:
+                return qdict[typ][domain]
+            except KeyError:
+                return ""
+        return remote.rshell.shell(command=command, fail_ok=fail_ok, print=print)
+
+    monkeypatch.setattr(remote.rdns, shell.__name__, shell)
     return qdict
 
 
 @pytest.fixture
-def mockdns(mockdns_base):
-    mockdns_base.update(
-        {
-            "A": {"some.domain": "1.1.1.1"},
-            "AAAA": {"some.domain": "fde5:cd7a:9e1c:3240:5a99:936f:cdac:53ae"},
-            "CNAME": {
-                "mta-sts.some.domain": "some.domain.",
-                "www.some.domain": "some.domain.",
-            },
-        }
-    )
+def mockdns_expected():
+    return {
+        "A": {"some.domain": "1.1.1.1"},
+        "AAAA": {"some.domain": "fde5:cd7a:9e1c:3240:5a99:936f:cdac:53ae"},
+        "CNAME": {
+            "mta-sts.some.domain": "some.domain.",
+            "www.some.domain": "some.domain.",
+        },
+    }
+
+
+@pytest.fixture(params=["plain", "with-dns-comments"])
+def mockdns(request, mockdns_base, mockdns_expected):
+    mockdns_base.update(deepcopy(mockdns_expected))
+    match request.param:
+        case "plain":
+            pass
+        case "with-dns-comments":
+            for typ, data in mockdns_base.items():
+                for host, result in data.items():
+                    mockdns_base[typ][host] = (
+                        ";; some unsuccessful attempt result\n"
+                        "; and another with a single semicolon\n"
+                        f"{result}"
+                    )
     return mockdns_base
 
 
 class TestPerformInitialChecks:
-    def test_perform_initial_checks_ok1(self, mockdns):
+    def test_perform_initial_checks_ok1(self, mockdns, mockdns_expected):
         remote_data = remote.rdns.perform_initial_checks("some.domain")
-        assert remote_data["A"] == mockdns["A"]["some.domain"]
-        assert remote_data["AAAA"] == mockdns["AAAA"]["some.domain"]
-        assert remote_data["MTA_STS"] == mockdns["CNAME"]["mta-sts.some.domain"]
-        assert remote_data["WWW"] == mockdns["CNAME"]["www.some.domain"]
+        assert remote_data["A"] == mockdns_expected["A"]["some.domain"]
+        assert remote_data["AAAA"] == mockdns_expected["AAAA"]["some.domain"]
+        assert remote_data["MTA_STS"] == mockdns_expected["CNAME"]["mta-sts.some.domain"]
+        assert remote_data["WWW"] == mockdns_expected["CNAME"]["www.some.domain"]
 
     @pytest.mark.parametrize("drop", ["A", "AAAA"])
     def test_perform_initial_checks_with_one_of_A_AAAA(self, mockdns, drop):