fix: drop conftest sys.path hack; rely on pytest pythonpath

tests/conftest.py

@@ -6,19 +6,15 @@ import importlib.util
 import json
 import shutil
 import socket
-import sys
 import time
 import urllib.error
 import urllib.request
 from pathlib import Path
 
-# Repo root on sys.path for `slack_export` / `server` (CI and local).
-REPO_ROOT = Path(__file__).resolve().parents[1]
-if str(REPO_ROOT) not in sys.path:
-    sys.path.insert(0, str(REPO_ROOT))
-
 import pytest
 
+REPO_ROOT = Path(__file__).resolve().parents[1]
+
 FIXTURE_EXPORT = REPO_ROOT / "tests" / "fixtures" / "mini-export"
 TEST_MANIFEST = REPO_ROOT / "tests" / "fixtures" / "test-manifest.json"
 
@@ -47,7 +43,6 @@ def fixture_export_path() -> Path:
 
 @pytest.fixture
 def export(fixture_export_path):
-    sys.path.insert(0, str(REPO_ROOT))
     from slack_export import SlackExport
 
     return SlackExport(fixture_export_path)
@@ -93,7 +88,6 @@ def review_server(tmp_path_factory):
     import threading
     from http.server import ThreadingHTTPServer
 
-    sys.path.insert(0, str(REPO_ROOT))
     from server import ReviewHandler
     from slack_export import SlackExport