fix(adapter,tests): isolate _load_providers tests from multi-path lookup

The 5 _load_providers tests were single-path-only: they wrote a
config.yaml to tmp_path and called _load_providers(str(tmp_path)),
expecting the lookup to read tmp_path/config.yaml.

After the multi-path fix in #7, _load_providers also checks:
  1. _CANONICAL_ADAPTER_DIR/config.yaml  (= /opt/adapter/config.yaml)
  2. _TEMPLATE_DIR/config.yaml           (= dirname(__file__)/config.yaml)
  3. ${config_path}/config.yaml          (the test's tmp_path)

Path 2 finds the repo's bundled config.yaml on the test runner's
disk before path 3 — the tests then see the bundled providers list
instead of the test's expected behavior.

Two surface changes:

  1. adapter.py — extract `os.path.dirname(os.path.abspath(__file__))`
     into a module-level `_TEMPLATE_DIR` constant, mirroring
     `_CANONICAL_ADAPTER_DIR`. Production behavior identical
     (resolved once at import). Tests can monkeypatch the module
     attribute to redirect the path-2 lookup.

  2. tests/test_adapter_prevalidate.py — 5 _load_providers tests
     monkeypatch `_CANONICAL_ADAPTER_DIR` and `_TEMPLATE_DIR` to a
     non-existent tmp subdir, isolating the test to the workspace
     config_path branch they always meant to test.

The 6th _load_providers test (`test_load_providers_parses_yaml_and_normalizes`)
already passed because path 2 returns 7 providers and that's what
that test expects — left unchanged.

Verification:
  pytest tests/                                 65/65 PASS
  pytest tests/test_adapter_prevalidate.py -k load_providers
                                                  6/6 PASS

Closes molecule-core#129 follow-up — the unit tests were the last
red on the template repo's CI.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

adapter.py

@@ -154,6 +154,12 @@ def _normalize_provider(entry: dict):
 # against the site-packages copy that bit us 2026-05-04 11:08Z.
 _CANONICAL_ADAPTER_DIR = "/opt/adapter"
 
+# Adjacent-to-adapter.py path. Module-level so tests can monkeypatch it
+# to redirect the path-2 lookup at a controlled tmp dir. Production code
+# resolves this once at import time and never touches it again — same
+# semantics as before.
+_TEMPLATE_DIR = os.path.dirname(os.path.abspath(__file__))
+
 
 def _load_providers(config_path: str) -> tuple:
     """Load the provider registry from the template's bundled config.yaml.
@@ -207,9 +213,7 @@ def _load_providers(config_path: str) -> tuple:
     a warning; the rest of the registry survives.
     """
     canonical_yaml = os.path.join(_CANONICAL_ADAPTER_DIR, "config.yaml")
-    template_yaml = os.path.join(
-        os.path.dirname(os.path.abspath(__file__)), "config.yaml"
-    )
+    template_yaml = os.path.join(_TEMPLATE_DIR, "config.yaml")
     workspace_yaml = os.path.join(config_path, "config.yaml")
     # Deduplicate while preserving order — _CANONICAL_ADAPTER_DIR and
     # the __file__ dir collide in dev/test (when imported from

tests/test_adapter_prevalidate.py

@@ -514,8 +514,15 @@ async def test_setup_auth_token_alone_satisfies_third_party_check(
 # ---- _load_providers / _resolve_provider unit tests ----
 
 
-def test_load_providers_returns_builtin_when_yaml_missing(tmp_path):
-    """FileNotFoundError path returns the in-code defaults verbatim."""
+def test_load_providers_returns_builtin_when_yaml_missing(tmp_path, monkeypatch):
+    """FileNotFoundError path returns the in-code defaults verbatim.
+
+    Monkeypatches the canonical + template paths to a non-existent dir
+    so only the workspace config_path is in scope. Without this, the
+    multi-path lookup picks up the repo-root config.yaml that ships
+    with the template (path 2 finds the bundled providers list and
+    returns it instead of falling through to builtins).
+    """
     _install_stubs()
     parent_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
     if parent_dir not in sys.path:
@@ -523,6 +530,10 @@ def test_load_providers_returns_builtin_when_yaml_missing(tmp_path):
     sys.modules.pop("adapter", None)
     import adapter as adapter_module
 
+    nonexistent = str(tmp_path / "_isolate_canonical")
+    monkeypatch.setattr(adapter_module, "_CANONICAL_ADAPTER_DIR", nonexistent)
+    monkeypatch.setattr(adapter_module, "_TEMPLATE_DIR", nonexistent)
+
     result = adapter_module._load_providers(str(tmp_path))
     assert result == adapter_module._BUILTIN_PROVIDERS
 
@@ -576,8 +587,12 @@ async def test_setup_routes_extra_providers(
     assert os.environ.get("ANTHROPIC_BASE_URL") == expected_url
 
 
-def test_load_providers_falls_back_on_malformed_yaml(tmp_path, caplog):
-    """Malformed YAML → log warning + fallback (don't kill boot)."""
+def test_load_providers_falls_back_on_malformed_yaml(tmp_path, caplog, monkeypatch):
+    """Malformed YAML → log warning + fallback (don't kill boot).
+
+    Isolated from the multi-path lookup by pinning canonical + template
+    dirs at a non-existent path; only the workspace config_path is read.
+    """
     _install_stubs()
     parent_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
     if parent_dir not in sys.path:
@@ -585,6 +600,10 @@ def test_load_providers_falls_back_on_malformed_yaml(tmp_path, caplog):
     sys.modules.pop("adapter", None)
     import adapter as adapter_module
 
+    nonexistent = str(tmp_path / "_isolate_canonical")
+    monkeypatch.setattr(adapter_module, "_CANONICAL_ADAPTER_DIR", nonexistent)
+    monkeypatch.setattr(adapter_module, "_TEMPLATE_DIR", nonexistent)
+
     (tmp_path / "config.yaml").write_text("providers: [not valid yaml: {{{")
 
     import logging
@@ -622,7 +641,7 @@ def test_resolve_provider_minimax_prefix_matches_minimax_provider():
     assert result2["name"] == "minimax"
 
 
-def test_load_providers_drops_bad_entry_keeps_rest(tmp_path, caplog):
+def test_load_providers_drops_bad_entry_keeps_rest(tmp_path, caplog, monkeypatch):
     """Per-entry isolation: one malformed entry shouldn't nuke the registry.
 
     Pre-fix: ``_load_providers`` built the registry via a generator inside
@@ -634,6 +653,9 @@ def test_load_providers_drops_bad_entry_keeps_rest(tmp_path, caplog):
 
     Post-fix: per-entry try/except drops the bad entry with a warning,
     rest of the registry survives.
+
+    Isolated from the multi-path lookup so only the test's tmp config.yaml
+    is read.
     """
     _install_stubs()
     parent_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
@@ -642,6 +664,10 @@ def test_load_providers_drops_bad_entry_keeps_rest(tmp_path, caplog):
     sys.modules.pop("adapter", None)
     import adapter as adapter_module
 
+    nonexistent = str(tmp_path / "_isolate_canonical")
+    monkeypatch.setattr(adapter_module, "_CANONICAL_ADAPTER_DIR", nonexistent)
+    monkeypatch.setattr(adapter_module, "_TEMPLATE_DIR", nonexistent)
+
     yaml_with_typo = textwrap.dedent("""
         providers:
           - name: good-zai
@@ -690,7 +716,7 @@ def test_load_providers_drops_bad_entry_keeps_rest(tmp_path, caplog):
     )
 
 
-def test_load_providers_string_as_prefix_does_not_split_into_chars(tmp_path, caplog):
+def test_load_providers_string_as_prefix_does_not_split_into_chars(tmp_path, caplog, monkeypatch):
     """A YAML field declared as list-of-strings but written as a bare
     string (operator forgot brackets) used to silently iterate over
     characters → ``('m','i','m','o','-')``. Post-fix: non-list value
@@ -705,6 +731,10 @@ def test_load_providers_string_as_prefix_does_not_split_into_chars(tmp_path, cap
     sys.modules.pop("adapter", None)
     import adapter as adapter_module
 
+    nonexistent = str(tmp_path / "_isolate_canonical")
+    monkeypatch.setattr(adapter_module, "_CANONICAL_ADAPTER_DIR", nonexistent)
+    monkeypatch.setattr(adapter_module, "_TEMPLATE_DIR", nonexistent)
+
     yaml_str_prefix = textwrap.dedent("""
         providers:
           - name: typo-prefix
@@ -723,7 +753,7 @@ def test_load_providers_string_as_prefix_does_not_split_into_chars(tmp_path, cap
     )
 
 
-def test_load_providers_drops_entry_without_name(tmp_path, caplog):
+def test_load_providers_drops_entry_without_name(tmp_path, caplog, monkeypatch):
     """An entry without ``name`` is operator error — no silent fallback
     to ``<unnamed>``. Drop the entry with a warning so the boot log
     surfaces the typo.
@@ -735,6 +765,10 @@ def test_load_providers_drops_entry_without_name(tmp_path, caplog):
     sys.modules.pop("adapter", None)
     import adapter as adapter_module
 
+    nonexistent = str(tmp_path / "_isolate_canonical")
+    monkeypatch.setattr(adapter_module, "_CANONICAL_ADAPTER_DIR", nonexistent)
+    monkeypatch.setattr(adapter_module, "_TEMPLATE_DIR", nonexistent)
+
     yaml_no_name = textwrap.dedent("""
         providers:
           - name: good