feat: add test suite, fix backend bugs, remove legacy artifacts 🧪

- Add 73-test suite across conftest, utils, admin API, reconciler, zone parser,
  and CoreDNS MySQL backend (all green, ~0.5s)
- Fix zone_exists filter using wrong column name (name → zone_name)
- Fix delete_zone missing dot_fqdn normalization on lookup
- Remove spurious unused `from config import config` in coredns_mysql.py
- Fix config loader to search module-relative path so tests find app.yml
  without needing a root-level config/ directory
- Remove legacy v1 Flask prototype (app.py), empty config.json, and
  duplicate root config/app.yml

tests/test_admin_api.py

@@ -0,0 +1,188 @@
+"""Tests for directdnsonly.app.api.admin — DNSAdminAPI handler methods."""
+import pytest
+from unittest.mock import MagicMock, patch
+from urllib.parse import parse_qs
+
+import cherrypy
+
+from directdnsonly.app.api.admin import DNSAdminAPI
+
+
+# ---------------------------------------------------------------------------
+# Fixtures
+# ---------------------------------------------------------------------------
+
+
+@pytest.fixture
+def save_queue():
+    return MagicMock()
+
+
+@pytest.fixture
+def delete_queue():
+    return MagicMock()
+
+
+@pytest.fixture
+def api(save_queue, delete_queue):
+    return DNSAdminAPI(save_queue, delete_queue, backend_registry=MagicMock())
+
+
+# ---------------------------------------------------------------------------
+# CMD_API_LOGIN_TEST
+# ---------------------------------------------------------------------------
+
+
+def test_login_test_returns_success(api):
+    result = api.CMD_API_LOGIN_TEST()
+    parsed = parse_qs(result)
+    assert parsed["error"] == ["0"]
+    assert parsed["text"] == ["Login OK"]
+
+
+# ---------------------------------------------------------------------------
+# _handle_exists — GET action=exists
+# ---------------------------------------------------------------------------
+
+
+def test_handle_exists_missing_domain_returns_error(api):
+    with patch.object(cherrypy, "response", MagicMock()):
+        result = api._handle_exists({"action": "exists"})
+    parsed = parse_qs(result)
+    assert parsed["error"] == ["1"]
+
+
+def test_handle_exists_unsupported_action_returns_error(api):
+    with patch.object(cherrypy, "response", MagicMock()):
+        result = api._handle_exists({"action": "rawsave"})
+    parsed = parse_qs(result)
+    assert parsed["error"] == ["1"]
+
+
+def test_handle_exists_domain_not_found(api):
+    with patch("directdnsonly.app.api.admin.check_zone_exists", return_value=False), \
+         patch("directdnsonly.app.api.admin.check_parent_domain_owner", return_value=False):
+        result = api._handle_exists({"action": "exists", "domain": "example.com"})
+
+    parsed = parse_qs(result)
+    assert parsed["error"] == ["0"]
+    assert parsed["exists"] == ["0"]
+
+
+def test_handle_exists_domain_found(api):
+    record = MagicMock()
+    record.hostname = "da1.example.com"
+
+    with patch("directdnsonly.app.api.admin.check_zone_exists", return_value=True), \
+         patch("directdnsonly.app.api.admin.get_domain_record", return_value=record):
+        result = api._handle_exists({"action": "exists", "domain": "example.com"})
+
+    parsed = parse_qs(result)
+    assert parsed["error"] == ["0"]
+    assert parsed["exists"] == ["1"]
+    assert "da1.example.com" in parsed["details"][0]
+
+
+def test_handle_exists_parent_found(api):
+    parent = MagicMock()
+    parent.hostname = "da2.example.com"
+
+    with patch("directdnsonly.app.api.admin.check_zone_exists", return_value=False), \
+         patch("directdnsonly.app.api.admin.check_parent_domain_owner", return_value=True), \
+         patch("directdnsonly.app.api.admin.get_parent_domain_record", return_value=parent):
+        result = api._handle_exists({
+            "action": "exists",
+            "domain": "sub.example.com",
+            "check_for_parent_domain": "1",
+        })
+
+    parsed = parse_qs(result)
+    assert parsed["error"] == ["0"]
+    assert parsed["exists"] == ["2"]
+    assert "da2.example.com" in parsed["details"][0]
+
+
+def test_handle_exists_no_parent_check_when_flag_absent(api):
+    """check_parent_domain_owner should not be called if flag not set."""
+    record = MagicMock()
+    record.hostname = "da1.example.com"
+
+    with patch("directdnsonly.app.api.admin.check_zone_exists", return_value=True), \
+         patch("directdnsonly.app.api.admin.check_parent_domain_owner") as mock_parent, \
+         patch("directdnsonly.app.api.admin.get_domain_record", return_value=record):
+        api._handle_exists({"action": "exists", "domain": "example.com"})
+
+    mock_parent.assert_not_called()
+
+
+# ---------------------------------------------------------------------------
+# _handle_rawsave
+# ---------------------------------------------------------------------------
+
+SAMPLE_ZONE = "$ORIGIN example.com.\n$TTL 300\nexample.com. 300 IN A 1.2.3.4\n"
+
+
+def test_rawsave_enqueues_item(api, save_queue):
+    with patch("directdnsonly.app.api.admin.validate_and_normalize_zone",
+               return_value=SAMPLE_ZONE), \
+         patch.object(cherrypy, "request", MagicMock(remote=MagicMock(ip="127.0.0.1"))):
+        result = api._handle_rawsave("example.com", {
+            "zone_file": SAMPLE_ZONE,
+            "hostname": "da1.example.com",
+            "username": "admin",
+        })
+
+    save_queue.put.assert_called_once()
+    item = save_queue.put.call_args[0][0]
+    assert item["domain"] == "example.com"
+    assert item["hostname"] == "da1.example.com"
+    assert item["username"] == "admin"
+    assert item["client_ip"] == "127.0.0.1"
+
+    parsed = parse_qs(result)
+    assert parsed["error"] == ["0"]
+
+
+def test_rawsave_missing_zone_file_raises(api):
+    with patch.object(cherrypy, "request", MagicMock(remote=MagicMock(ip="127.0.0.1"))):
+        with pytest.raises(ValueError, match="Missing zone file"):
+            api._handle_rawsave("example.com", {})
+
+
+def test_rawsave_invalid_zone_raises(api):
+    with patch("directdnsonly.app.api.admin.validate_and_normalize_zone",
+               side_effect=ValueError("Invalid zone data: bad record")), \
+         patch.object(cherrypy, "request", MagicMock(remote=MagicMock(ip="127.0.0.1"))):
+        with pytest.raises(ValueError, match="Invalid zone data"):
+            api._handle_rawsave("example.com", {"zone_file": "garbage"})
+
+
+# ---------------------------------------------------------------------------
+# _handle_delete
+# ---------------------------------------------------------------------------
+
+
+def test_delete_enqueues_item(api, delete_queue):
+    with patch.object(cherrypy, "request", MagicMock(remote=MagicMock(ip="10.0.0.1"))):
+        result = api._handle_delete("example.com", {
+            "hostname": "da1.example.com",
+            "username": "admin",
+        })
+
+    delete_queue.put.assert_called_once()
+    item = delete_queue.put.call_args[0][0]
+    assert item["domain"] == "example.com"
+    assert item["hostname"] == "da1.example.com"
+    assert item["client_ip"] == "10.0.0.1"
+
+    parsed = parse_qs(result)
+    assert parsed["error"] == ["0"]
+
+
+def test_delete_missing_params_uses_empty_strings(api, delete_queue):
+    with patch.object(cherrypy, "request", MagicMock(remote=MagicMock(ip="127.0.0.1"))):
+        api._handle_delete("example.com", {})
+
+    item = delete_queue.put.call_args[0][0]
+    assert item["hostname"] == ""
+    assert item["username"] == ""