Speed up test suite with pytest-xdist

.gitignore

@@ -1,5 +1,6 @@
 .cache
 .coverage
+.coverage.*
 .mypy_cache/
 __pycache__/
 uvicorn.egg-info/

pyproject.toml

@@ -85,7 +85,7 @@ disallow_untyped_defs = false
 check_untyped_defs = true
 
 [tool.pytest.ini_options]
-addopts = "-rxXs --strict-config --strict-markers"
+addopts = "-rxXs --strict-config --strict-markers -n 8"
 xfail_strict = true
 filterwarnings = [
     "error",
@@ -95,6 +95,7 @@ filterwarnings = [
 ]
 
 [tool.coverage.run]
+parallel = true
 source_pkgs = ["uvicorn", "tests"]
 plugins = ["coverage_conditional_plugin"]
 omit = ["uvicorn/workers.py", "uvicorn/__main__.py"]
@@ -125,6 +126,7 @@ exclude_lines = [
 py-win32 = "sys_platform == 'win32'"
 py-not-win32 = "sys_platform != 'win32'"
 py-linux = "sys_platform == 'linux'"
+py-not-linux = "sys_platform != 'linux'"
 py-darwin = "sys_platform == 'darwin'"
 py-gte-39 = "sys_version_info >= (3, 9)"
 py-lt-39 = "sys_version_info < (3, 9)"

requirements.txt

@@ -17,13 +17,15 @@ twine==6.0.1
 ruff==0.8.3
 pytest==8.3.4
 pytest-mock==3.14.0
+pytest-xdist[psutil]==3.6.0
 mypy==1.13.0
 types-click==7.1.8
 types-pyyaml==6.0.12.20240917
 trustme==1.2.0
 cryptography==44.0.0
 coverage==7.6.9
 coverage-conditional-plugin==0.9.0
+coverage-enable-subprocess==1.0
 httpx==0.28.1
 
 # Documentation

scripts/coverage

@@ -8,4 +8,5 @@ export SOURCE_FILES="uvicorn tests"
 
 set -x
 
+${PREFIX}coverage combine
 ${PREFIX}coverage report

scripts/test

@@ -11,6 +11,8 @@ if [ -z $GITHUB_ACTIONS ]; then
     scripts/check
 fi
 
+export COVERAGE_PROCESS_START=$(pwd)/pyproject.toml
+
 ${PREFIX}coverage run --debug config -m pytest "$@"
 
 if [ -z $GITHUB_ACTIONS ]; then

tests/supervisors/test_reload.py

@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import platform
 import signal
 import socket
 import sys
@@ -24,11 +23,8 @@
     WatchFilesReload = None  # type: ignore[misc,assignment]
 
 
-# TODO: Investigate why this is flaky on MacOS M1.
-skip_if_m1 = pytest.mark.skipif(
-    sys.platform == "darwin" and platform.processor() == "arm",
-    reason="Flaky on MacOS M1",
-)
+# TODO: Investigate why this is flaky on MacOS, and Windows.
+skip_non_linux = pytest.mark.skipif(sys.platform in ("darwin", "win32"), reason="Flaky on Windows and MacOS")
 
 
 def run(sockets: list[socket.socket] | None) -> None:
@@ -141,8 +137,12 @@ def test_should_not_reload_when_python_file_in_excluded_subdir_is_changed(self,
 
             reloader.shutdown()
 
-    @pytest.mark.parametrize("reloader_class, result", [(StatReload, False), (WatchFilesReload, True)])
-    def test_reload_when_pattern_matched_file_is_changed(self, result: bool, touch_soon: Callable[[Path], None]):
+    @pytest.mark.parametrize(
+        "reloader_class, result", [(StatReload, False), pytest.param(WatchFilesReload, True, marks=skip_non_linux)]
+    )
+    def test_reload_when_pattern_matched_file_is_changed(
+        self, result: bool, touch_soon: Callable[[Path], None]
+    ):  # pragma: py-not-linux
         file = self.reload_path / "app" / "js" / "main.js"
 
         with as_cwd(self.reload_path):
@@ -153,10 +153,10 @@ def test_reload_when_pattern_matched_file_is_changed(self, result: bool, touch_s
 
             reloader.shutdown()
 
-    @pytest.mark.parametrize("reloader_class", [pytest.param(WatchFilesReload, marks=skip_if_m1)])
+    @pytest.mark.parametrize("reloader_class", [pytest.param(WatchFilesReload, marks=skip_non_linux)])
     def test_should_not_reload_when_exclude_pattern_match_file_is_changed(
         self, touch_soon: Callable[[Path], None]
-    ):  # pragma: py-darwin
+    ):  # pragma: py-not-linux
         python_file = self.reload_path / "app" / "src" / "main.py"
         css_file = self.reload_path / "app" / "css" / "main.css"
         js_file = self.reload_path / "app" / "js" / "main.js"
@@ -188,8 +188,10 @@ def test_should_not_reload_when_dot_file_is_changed(self, touch_soon: Callable[[
 
             reloader.shutdown()
 
-    @pytest.mark.parametrize("reloader_class", [StatReload, WatchFilesReload])
-    def test_should_reload_when_directories_have_same_prefix(self, touch_soon: Callable[[Path], None]):
+    @pytest.mark.parametrize("reloader_class", [StatReload, pytest.param(WatchFilesReload, marks=skip_non_linux)])
+    def test_should_reload_when_directories_have_same_prefix(
+        self, touch_soon: Callable[[Path], None]
+    ):  # pragma: py-not-linux
         app_dir = self.reload_path / "app"
         app_file = app_dir / "src" / "main.py"
         app_first_dir = self.reload_path / "app_first"
@@ -210,9 +212,11 @@ def test_should_reload_when_directories_have_same_prefix(self, touch_soon: Calla
 
     @pytest.mark.parametrize(
         "reloader_class",
-        [StatReload, pytest.param(WatchFilesReload, marks=skip_if_m1)],
+        [StatReload, pytest.param(WatchFilesReload, marks=skip_non_linux)],
     )
-    def test_should_not_reload_when_only_subdirectory_is_watched(self, touch_soon: Callable[[Path], None]):
+    def test_should_not_reload_when_only_subdirectory_is_watched(
+        self, touch_soon: Callable[[Path], None]
+    ):  # pragma: py-not-linux
         app_dir = self.reload_path / "app"
         app_dir_file = self.reload_path / "app" / "src" / "main.py"
         root_file = self.reload_path / "main.py"
@@ -229,8 +233,8 @@ def test_should_not_reload_when_only_subdirectory_is_watched(self, touch_soon: C
 
         reloader.shutdown()
 
-    @pytest.mark.parametrize("reloader_class", [pytest.param(WatchFilesReload, marks=skip_if_m1)])
-    def test_override_defaults(self, touch_soon: Callable[[Path], None]) -> None:  # pragma: py-darwin
+    @pytest.mark.parametrize("reloader_class", [pytest.param(WatchFilesReload, marks=skip_non_linux)])
+    def test_override_defaults(self, touch_soon: Callable[[Path], None]) -> None:  # pragma: py-not-linux
         dotted_file = self.reload_path / ".dotted"
         dotted_dir_file = self.reload_path / ".dotted_dir" / "file.txt"
         python_file = self.reload_path / "main.py"
@@ -251,8 +255,8 @@ def test_override_defaults(self, touch_soon: Callable[[Path], None]) -> None:  #
 
             reloader.shutdown()
 
-    @pytest.mark.parametrize("reloader_class", [pytest.param(WatchFilesReload, marks=skip_if_m1)])
-    def test_explicit_paths(self, touch_soon: Callable[[Path], None]) -> None:  # pragma: py-darwin
+    @pytest.mark.parametrize("reloader_class", [pytest.param(WatchFilesReload, marks=skip_non_linux)])
+    def test_explicit_paths(self, touch_soon: Callable[[Path], None]) -> None:  # pragma: py-not-linux
         dotted_file = self.reload_path / ".dotted"
         non_dotted_file = self.reload_path / "ext" / "ext.jpg"
         python_file = self.reload_path / "main.py"

tests/test_server.py

@@ -64,7 +64,9 @@ async def app(scope: Scope, receive: ASGIReceiveCallable, send: ASGISendCallable
 @pytest.mark.parametrize("exception_signal", signals)
 @pytest.mark.parametrize("capture_signal", signal_captures)
 async def test_server_interrupt(
-    exception_signal: signal.Signals, capture_signal: Callable[[signal.Signals], AbstractContextManager[None]]
+    exception_signal: signal.Signals,
+    capture_signal: Callable[[signal.Signals], AbstractContextManager[None]],
+    unused_tcp_port: int,
 ):  # pragma: py-win32
     """Test interrupting a Server that is run explicitly inside asyncio"""
 
@@ -73,7 +75,7 @@ async def interrupt_running(srv: Server):
             await asyncio.sleep(0.01)
         signal.raise_signal(exception_signal)
 
-    server = Server(Config(app=dummy_app, loop="asyncio"))
+    server = Server(Config(app=dummy_app, loop="asyncio", port=unused_tcp_port))
     asyncio.create_task(interrupt_running(server))
     with capture_signal(exception_signal) as witness:
         await server.serve()

uvicorn/config.py

@@ -138,7 +138,7 @@ def resolve_reload_patterns(patterns_list: list[str], directories_list: list[str
         # Special case for the .* pattern, otherwise this would only match
         # hidden directories which is probably undesired
         if pattern == ".*":
-            continue  # pragma: py-darwin
+            continue  # pragma: py-not-linux
         patterns.append(pattern)
         if is_dir(Path(pattern)):
             directories.append(Path(pattern))

uvicorn/server.py

@@ -119,7 +119,7 @@ def create_protocol(
 
             def _share_socket(
                 sock: socket.SocketType,
-            ) -> socket.SocketType:  # pragma py-linux pragma: py-darwin
+            ) -> socket.SocketType:  # pragma py-not-win32
                 # Windows requires the socket be explicitly shared across
                 # multiple workers (processes).
                 from socket import fromshare  # type: ignore[attr-defined]