chore: simplify dev port lookup and isolate settings tests

Resolve the shared backend port once for make dev and reuse it in the child make. Keep pure configuration tests independent of local credentials and URLs without altering integration database settings.

Makefile

@@ -14,7 +14,7 @@ install: ## Sync project-local dependencies from both lockfiles
 	cd apps/web && bun install --frozen-lockfile
 
 dev: ## Start PostgreSQL and run the native backend and web together
-	$(MAKE) --jobs=2 backend-dev web-dev
+	$(MAKE) --jobs=2 backend-dev web-dev BACKEND_PORT=$(BACKEND_PORT)
 
 db-up: ## Start local PostgreSQL and wait until ready
 	docker compose up -d --wait postgres

tests/conftest.py

@@ -1,4 +1,5 @@
 import asyncio
+import os
 import time
 from collections.abc import Callable, Iterator
 from typing import Any
@@ -19,6 +20,15 @@ from ai_platform.infrastructure.persistence.models import AIProfile, AppCredenti
 from ai_platform.platform.security import digest
 
 
+@pytest.fixture
+def isolated_settings(monkeypatch: pytest.MonkeyPatch) -> None:
+    """Keep pure configuration tests independent of operator credentials and local URLs."""
+    monkeypatch.setitem(Settings.model_config, "env_file", None)
+    for name in tuple(os.environ):
+        if name.startswith("AI_PLATFORM_"):
+            monkeypatch.delenv(name)
+
+
 @pytest.fixture
 def valid_run_payload():
     return {

tests/test_aihub_settings.py

@@ -4,6 +4,7 @@ from pydantic import SecretStr, ValidationError
 from ai_platform.infrastructure.config.settings import Settings
 
 _TEST_DATABASE_URL = "postgresql+asyncpg://test:test@localhost/ai_platform_test"
+pytestmark = pytest.mark.usefixtures("isolated_settings")
 
 
 @pytest.mark.parametrize(

tests/test_dev_commands.py

@@ -35,7 +35,9 @@ def test_dev_uses_the_same_backend_port_for_both_servers(
     (tmp_path / ".env").write_text(config)
     # Only the port lookup executes during dry-run; bypass uv project discovery in this fixture.
     uv = tmp_path / "uv"
-    uv.write_text(f'#!/bin/sh\nshift 3\nexec {shlex.quote(sys.executable)} "$@"\n')
+    uv.write_text(
+        f'#!/bin/sh\necho port-lookup >&2\nshift 3\nexec {shlex.quote(sys.executable)} "$@"\n'
+    )
     uv.chmod(0o700)
     environment = os.environ.copy()
     for name in ("BACKEND_PORT", "MAKEFLAGS", "MFLAGS", "MAKEOVERRIDES"):
@@ -62,3 +64,5 @@ def test_dev_uses_the_same_backend_port_for_both_servers(
     assert "alembic" not in result.stdout
     assert secret not in result.stdout + result.stderr
     assert "AI_PLATFORM_OPENAI_API_KEY" not in result.stdout + result.stderr
+    expected_lookups = 0 if environment_port is not None or argument_port is not None else 1
+    assert result.stderr.count("port-lookup") == expected_lookups

tests/test_notifications.py

@@ -27,6 +27,7 @@ NOW = datetime(2026, 9, 28, tzinfo=UTC)
 SECRET = "test-only-webhook-secret-32-characters-long"
 
 
+@pytest.mark.usefixtures("isolated_settings")
 def test_webhook_configuration_requires_pair_and_safe_url():
     with pytest.raises(ValidationError):
         AppWebhook.model_validate({"url": "https://omni.example.invalid/events"})