test(egress): ratchet egress_addon_core coverage to >=90%

Third per-module ratchet under ADR 0004. Add a parsing/serialization
suite for the egress engine's core:

- route validation rejections: payload/route shape, host, auth pairing,
  git block, every matches sub-field (paths/methods/headers type +
  regex-compile + unknown-key), and the dlp block (detector type/name,
  outbound_on_match, unknown key)
- a full valid route round-trips; detectors:false disables
- parse_config log-level validation + load_config invalid-YAML
- route_to_yaml_dict: minimal/auth/git/dlp/matches with default-omission
- evaluate_matches: exact/prefix/regex paths, method filter, exact +
  regex header matching (match and non-match)

egress_addon_core.py: 84% -> 99%. The two remaining missed statements
are defensive guards (an unreachable separator-return and a
no-matching-path-type fallthrough).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NkwFXLFff9PYPy4wgVBJp9

tests/unit/test_egress_core_parsing.py

@@ -0,0 +1,297 @@
+"""Unit: egress_addon_core route parsing, serialization, and match
+evaluation error/edge branches (coverage ratchet, ADR 0004).
+
+Complements test_egress_addon_core.py — focuses on the validation
+rejections, the Route->YAML serializer, and evaluate_matches."""
+
+from __future__ import annotations
+
+import unittest
+
+from bot_bottle.egress_addon_core import (
+    HeaderMatch,
+    MatchEntry,
+    PathMatch,
+    Route,
+    evaluate_matches,
+    load_config,
+    parse_config,
+    parse_routes,
+    route_to_yaml_dict,
+)
+
+
+def _route(d: dict[str, object]) -> Route:
+    return parse_routes({"routes": [d]})[0]
+
+
+class TestRouteValidationErrors(unittest.TestCase):
+    def _bad(self, d: dict[str, object]) -> None:
+        with self.assertRaises(ValueError):
+            parse_routes({"routes": [d]})
+
+    # routes-payload shape
+    def test_payload_not_dict(self) -> None:
+        with self.assertRaises(ValueError):
+            parse_routes(["nope"])
+
+    def test_routes_not_list(self) -> None:
+        with self.assertRaises(ValueError):
+            parse_routes({"routes": "nope"})
+
+    def test_route_not_dict(self) -> None:
+        with self.assertRaises(ValueError):
+            parse_routes({"routes": ["nope"]})
+
+    def test_host_missing(self) -> None:
+        self._bad({})
+
+    def test_unknown_route_key(self) -> None:
+        self._bad({"host": "h", "bogus": 1})
+
+    # auth
+    def test_auth_scheme_without_token_env(self) -> None:
+        self._bad({"host": "h", "auth_scheme": "Bearer"})
+
+    def test_auth_scheme_wrong_type(self) -> None:
+        self._bad({"host": "h", "auth_scheme": 5, "token_env": "T"})
+
+    # git
+    def test_git_not_dict(self) -> None:
+        self._bad({"host": "h", "git": "yes"})
+
+    def test_git_fetch_not_bool(self) -> None:
+        self._bad({"host": "h", "git": {"fetch": "yes"}})
+
+    def test_git_unknown_key(self) -> None:
+        self._bad({"host": "h", "git": {"fetch": True, "push": True}})
+
+    # matches: paths
+    def test_matches_not_list(self) -> None:
+        self._bad({"host": "h", "matches": "x"})
+
+    def test_match_entry_not_dict(self) -> None:
+        self._bad({"host": "h", "matches": ["x"]})
+
+    def test_paths_not_list(self) -> None:
+        self._bad({"host": "h", "matches": [{"paths": "x"}]})
+
+    def test_path_not_dict(self) -> None:
+        self._bad({"host": "h", "matches": [{"paths": ["x"]}]})
+
+    def test_path_bad_type(self) -> None:
+        self._bad({"host": "h", "matches": [{"paths": [{"type": "bogus", "value": "/x"}]}]})
+
+    def test_path_empty_value(self) -> None:
+        self._bad({"host": "h", "matches": [{"paths": [{"value": ""}]}]})
+
+    def test_path_value_missing_slash(self) -> None:
+        self._bad({"host": "h", "matches": [{"paths": [{"type": "prefix", "value": "x"}]}]})
+
+    def test_path_bad_regex(self) -> None:
+        self._bad({"host": "h", "matches": [{"paths": [{"type": "regex", "value": "("}]}]})
+
+    def test_path_unknown_key(self) -> None:
+        self._bad({"host": "h", "matches": [{"paths": [{"value": "/x", "z": 1}]}]})
+
+    # matches: methods
+    def test_methods_not_list(self) -> None:
+        self._bad({"host": "h", "matches": [{"methods": "GET"}]})
+
+    def test_method_not_string(self) -> None:
+        self._bad({"host": "h", "matches": [{"methods": [5]}]})
+
+    def test_method_invalid(self) -> None:
+        self._bad({"host": "h", "matches": [{"methods": ["FETCH"]}]})
+
+    # matches: headers
+    def test_headers_not_list(self) -> None:
+        self._bad({"host": "h", "matches": [{"headers": "x"}]})
+
+    def test_header_not_dict(self) -> None:
+        self._bad({"host": "h", "matches": [{"headers": ["x"]}]})
+
+    def test_header_name_empty(self) -> None:
+        self._bad({"host": "h", "matches": [{"headers": [{"name": "", "value": "v"}]}]})
+
+    def test_header_value_not_string(self) -> None:
+        self._bad({"host": "h", "matches": [{"headers": [{"name": "X", "value": 1}]}]})
+
+    def test_header_bad_type(self) -> None:
+        self._bad({"host": "h", "matches": [{"headers": [{"name": "X", "value": "v", "type": "z"}]}]})
+
+    def test_header_bad_regex(self) -> None:
+        self._bad({"host": "h", "matches": [{"headers": [{"name": "X", "value": "(", "type": "regex"}]}]})
+
+    def test_header_unknown_key(self) -> None:
+        self._bad({"host": "h", "matches": [{"headers": [{"name": "X", "value": "v", "z": 1}]}]})
+
+    # dlp
+    def test_dlp_not_dict(self) -> None:
+        self._bad({"host": "h", "dlp": "x"})
+
+    def test_dlp_detectors_wrong_type(self) -> None:
+        self._bad({"host": "h", "dlp": {"outbound_detectors": "x"}})
+
+    def test_dlp_detector_name_invalid(self) -> None:
+        self._bad({"host": "h", "dlp": {"outbound_detectors": ["bogus"]}})
+
+    def test_dlp_detector_item_not_string(self) -> None:
+        self._bad({"host": "h", "dlp": {"outbound_detectors": [5]}})
+
+    def test_dlp_on_match_invalid(self) -> None:
+        self._bad({"host": "h", "dlp": {"outbound_on_match": "maybe"}})
+
+    def test_dlp_unknown_key(self) -> None:
+        self._bad({"host": "h", "dlp": {"bogus": 1}})
+
+
+class TestRouteValidAccepts(unittest.TestCase):
+    def test_full_route_parses(self) -> None:
+        r = _route({
+            "host": "api.example.com",
+            "auth_scheme": "Bearer",
+            "token_env": "TOK",
+            "matches": [{
+                "paths": [{"type": "exact", "value": "/v1"}],
+                "methods": ["get", "post"],
+                "headers": [{"name": "X-Env", "value": "prod"}],
+            }],
+            "git": {"fetch": True},
+            "dlp": {
+                "outbound_detectors": ["token_patterns"],
+                "inbound_detectors": ["naive_injection_detection"],
+                "outbound_on_match": "block",
+            },
+        })
+        self.assertEqual("api.example.com", r.host)
+        self.assertEqual(("GET", "POST"), r.matches[0].methods)
+        self.assertTrue(r.git_fetch)
+        self.assertEqual("block", r.outbound_on_match)
+
+    def test_dlp_detectors_false_disables(self) -> None:
+        r = _route({"host": "h", "dlp": {"outbound_detectors": False}})
+        self.assertEqual((), r.outbound_detectors)
+
+
+class TestParseConfig(unittest.TestCase):
+    def test_log_must_be_valid_level(self) -> None:
+        with self.assertRaises(ValueError):
+            parse_config({"log": 5, "routes": []})
+
+    def test_log_true_rejected(self) -> None:
+        with self.assertRaises(ValueError):
+            parse_config({"log": True, "routes": []})
+
+    def test_top_level_not_dict(self) -> None:
+        with self.assertRaises(ValueError):
+            parse_config(["x"])
+
+    def test_load_config_invalid_yaml(self) -> None:
+        with self.assertRaises(ValueError):
+            load_config("routes: [unterminated\n")
+
+
+class TestRouteToYamlDict(unittest.TestCase):
+    def test_minimal(self) -> None:
+        self.assertEqual({"host": "h"}, route_to_yaml_dict(Route(host="h")))
+
+    def test_auth_fields(self) -> None:
+        d = route_to_yaml_dict(Route(host="h", auth_scheme="Bearer", token_env="T"))
+        self.assertEqual("Bearer", d["auth_scheme"])
+        self.assertEqual("T", d["token_env"])
+
+    def test_git_fetch(self) -> None:
+        d = route_to_yaml_dict(Route(host="h", git_fetch=True))
+        self.assertEqual({"fetch": True}, d["git"])
+
+    def test_dlp_fields(self) -> None:
+        d = route_to_yaml_dict(Route(
+            host="h",
+            outbound_detectors=("token_patterns",),
+            inbound_detectors=("naive_injection_detection",),
+            outbound_on_match="redact",
+        ))
+        self.assertEqual(
+            {
+                "outbound_detectors": ["token_patterns"],
+                "inbound_detectors": ["naive_injection_detection"],
+                "outbound_on_match": "redact",
+            },
+            d["dlp"],
+        )
+
+    def test_matches_serialization_omits_defaults(self) -> None:
+        route = Route(host="h", matches=(MatchEntry(
+            paths=(
+                PathMatch(type="prefix", value="/p"),   # default type -> omitted
+                PathMatch(type="exact", value="/e"),    # non-default -> kept
+            ),
+            methods=("GET",),
+            headers=(
+                HeaderMatch(name="X", value="v"),                    # exact -> omitted
+                HeaderMatch(name="Y", value="r", type="regex"),      # regex -> kept
+            ),
+        ),))
+        d = route_to_yaml_dict(route)
+        matches = d["matches"]
+        assert isinstance(matches, list)
+        entry = matches[0]
+        self.assertEqual(
+            [{"value": "/p"}, {"value": "/e", "type": "exact"}],
+            entry["paths"],
+        )
+        self.assertEqual(["GET"], entry["methods"])
+        self.assertEqual(
+            [{"name": "X", "value": "v"}, {"name": "Y", "value": "r", "type": "regex"}],
+            entry["headers"],
+        )
+
+
+class TestEvaluateMatches(unittest.TestCase):
+    def _route_with(self, entry: MatchEntry) -> Route:
+        return Route(host="h", matches=(entry,))
+
+    def test_empty_matches_allows_all(self) -> None:
+        self.assertTrue(evaluate_matches(Route(host="h"), "/anything", "GET"))
+
+    def test_exact_path(self) -> None:
+        r = self._route_with(MatchEntry(paths=(PathMatch("exact", "/a"),)))
+        self.assertTrue(evaluate_matches(r, "/a", "GET"))
+        self.assertFalse(evaluate_matches(r, "/a/b", "GET"))
+
+    def test_prefix_path_boundary(self) -> None:
+        r = self._route_with(MatchEntry(paths=(PathMatch("prefix", "/a"),)))
+        self.assertTrue(evaluate_matches(r, "/a/b", "GET"))
+        self.assertFalse(evaluate_matches(r, "/ab", "GET"))
+
+    def test_regex_path(self) -> None:
+        import re
+        r = self._route_with(MatchEntry(
+            paths=(PathMatch("regex", r"/v\d+", compiled=re.compile(r"/v\d+")),),
+        ))
+        self.assertTrue(evaluate_matches(r, "/v1", "GET"))
+        self.assertFalse(evaluate_matches(r, "/x", "GET"))
+
+    def test_method_filter(self) -> None:
+        r = self._route_with(MatchEntry(methods=("POST",)))
+        self.assertTrue(evaluate_matches(r, "/x", "post"))
+        self.assertFalse(evaluate_matches(r, "/x", "GET"))
+
+    def test_header_exact(self) -> None:
+        r = self._route_with(MatchEntry(headers=(HeaderMatch("X-Env", "prod"),)))
+        self.assertTrue(evaluate_matches(r, "/x", "GET", {"x-env": "prod"}))
+        self.assertFalse(evaluate_matches(r, "/x", "GET", {"x-env": "dev"}))
+        self.assertFalse(evaluate_matches(r, "/x", "GET", {}))
+
+    def test_header_regex(self) -> None:
+        import re
+        r = self._route_with(MatchEntry(
+            headers=(HeaderMatch("X-Env", r"pr.*", type="regex", compiled=re.compile(r"pr.*")),),
+        ))
+        self.assertTrue(evaluate_matches(r, "/x", "GET", {"x-env": "prod"}))
+        self.assertFalse(evaluate_matches(r, "/x", "GET", {"x-env": "dev"}))
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/unit/test_yaml_subset.py

@@ -325,5 +325,137 @@ class TestFrontmatter(unittest.TestCase):
         self.assertEqual("\nline one\n\nline three\n", body)
 
 
+class TestEdgeAndErrorBranches(unittest.TestCase):
+    """Reachable error / edge branches of the parser (coverage ratchet)."""
+
+    # --- scalars / comments -------------------------------------------------
+    def test_hash_not_preceded_by_space_is_literal(self) -> None:
+        self.assertEqual({"k": "a#b"}, parse_yaml_subset("k: a#b\n"))
+
+    def test_blank_line_between_entries_skipped(self) -> None:
+        self.assertEqual({"a": 1, "b": 2}, parse_yaml_subset("a: 1\n\nb: 2\n"))
+
+    def test_unterminated_quote_single_char(self) -> None:
+        with self.assertRaises(YamlSubsetError):
+            parse_yaml_subset('k: "\n')
+
+    def test_bad_double_quote_escape(self) -> None:
+        with self.assertRaises(YamlSubsetError):
+            parse_yaml_subset('k: "\\x"\n')
+
+    # --- inline list / dict -------------------------------------------------
+    def test_inline_dict_empty_value_is_empty_string(self) -> None:
+        self.assertEqual({"k": {"a": ""}}, parse_yaml_subset("k: {a: }\n"))
+
+    def test_unterminated_inline_list(self) -> None:
+        with self.assertRaises(YamlSubsetError):
+            parse_yaml_subset("k: [a, b\n")
+
+    def test_empty_inline_list(self) -> None:
+        self.assertEqual({"k": []}, parse_yaml_subset("k: []\n"))
+
+    def test_unterminated_inline_dict(self) -> None:
+        with self.assertRaises(YamlSubsetError):
+            parse_yaml_subset("k: {a: 1\n")
+
+    def test_empty_inline_dict(self) -> None:
+        self.assertEqual({"k": {}}, parse_yaml_subset("k: {}\n"))
+
+    def test_inline_dict_entry_missing_colon(self) -> None:
+        with self.assertRaises(YamlSubsetError):
+            parse_yaml_subset("k: {a}\n")
+
+    def test_inline_dict_non_bare_key(self) -> None:
+        with self.assertRaises(YamlSubsetError):
+            parse_yaml_subset("k: {$x: 1}\n")
+
+    def test_quoted_comma_in_flow_is_one_item(self) -> None:
+        self.assertEqual({"k": ["a", "b, c"]}, parse_yaml_subset("k: [a, 'b, c']\n"))
+
+    # --- block mapping / list ----------------------------------------------
+    def test_line_missing_colon_separator(self) -> None:
+        with self.assertRaises(YamlSubsetError):
+            parse_yaml_subset("justtext\n")
+
+    def test_single_quoted_key_rejected_as_non_bare(self) -> None:
+        with self.assertRaises(YamlSubsetError):
+            parse_yaml_subset("'ab': v\n")
+
+    def test_list_item_at_mapping_indent_rejected(self) -> None:
+        with self.assertRaises(YamlSubsetError):
+            parse_yaml_subset("a: 1\n- b\n")
+
+    def test_empty_block_value_is_none(self) -> None:
+        self.assertEqual({"k": None}, parse_yaml_subset("k:\n"))
+
+    def test_list_item_first_key_non_bare(self) -> None:
+        with self.assertRaises(YamlSubsetError):
+            parse_yaml_subset("k:\n  - $x: 1\n")
+
+    def test_bare_dash_nested_block_list(self) -> None:
+        self.assertEqual(
+            {"k": [["nested"]]},
+            parse_yaml_subset("k:\n  -\n    - nested\n"),
+        )
+
+    def test_list_item_quoted_colon_is_scalar(self) -> None:
+        self.assertEqual({"k": ["a:b"]}, parse_yaml_subset('k:\n  - "a:b"\n'))
+
+    def test_list_item_mapping_with_nested_block(self) -> None:
+        self.assertEqual(
+            {"k": [{"a": {"b": 2}}]},
+            parse_yaml_subset("k:\n  - a:\n        b: 2\n"),
+        )
+
+    def test_list_item_sibling_key_empty_is_none(self) -> None:
+        self.assertEqual(
+            {"k": [{"a": 1, "b": None}]},
+            parse_yaml_subset("k:\n  - a: 1\n    b:\n"),
+        )
+
+    def test_list_item_duplicate_key(self) -> None:
+        with self.assertRaises(YamlSubsetError):
+            parse_yaml_subset("k:\n  - a: 1\n    a: 2\n")
+
+    def test_list_item_sibling_key_non_bare(self) -> None:
+        with self.assertRaises(YamlSubsetError):
+            parse_yaml_subset("k:\n  - a: 1\n    $b: 2\n")
+
+    # --- document-level rejections -----------------------------------------
+    def test_block_scalar_folded_rejected(self) -> None:
+        with self.assertRaises(YamlSubsetError):
+            parse_yaml_subset(">folded\n")
+
+    def test_block_scalar_literal_rejected(self) -> None:
+        with self.assertRaises(YamlSubsetError):
+            parse_yaml_subset("|literal\n")
+
+    def test_anchor_rejected(self) -> None:
+        with self.assertRaises(YamlSubsetError):
+            parse_yaml_subset("k: &a x\n")
+
+    def test_ampersand_in_quoted_value_allowed(self) -> None:
+        self.assertEqual({"k": "a & b"}, parse_yaml_subset('k: "a & b"\n'))
+
+    def test_yaml_tag_rejected(self) -> None:
+        with self.assertRaises(YamlSubsetError):
+            parse_yaml_subset("k: !!str x\n")
+
+    def test_only_comments_is_empty_mapping(self) -> None:
+        self.assertEqual({}, parse_yaml_subset("# just a comment\n"))
+
+    def test_top_level_not_column_zero(self) -> None:
+        with self.assertRaises(YamlSubsetError):
+            parse_yaml_subset("  k: 1\n")
+
+    def test_top_level_list_rejected(self) -> None:
+        with self.assertRaises(YamlSubsetError):
+            parse_yaml_subset("- a\n- b\n")
+
+    # --- frontmatter --------------------------------------------------------
+    def test_frontmatter_empty_text(self) -> None:
+        self.assertEqual(({}, ""), parse_frontmatter(""))
+
+
 if __name__ == "__main__":
     unittest.main()