Added type hints to Tests/helper.py

Tests/helper.py

@@ -11,6 +11,7 @@
 import sysconfig
 import tempfile
 from io import BytesIO
+from typing import Any, Callable, Sequence
 
 import pytest
 from packaging.version import parse as parse_version
@@ -19,42 +20,40 @@
 
 logger = logging.getLogger(__name__)
 
-
-HAS_UPLOADER = False
-
+uploader = None
 if os.environ.get("SHOW_ERRORS"):
-    # local img.show for errors.
-    HAS_UPLOADER = True
-
-    class test_image_results:
-        @staticmethod
-        def upload(a, b):
-            a.show()
-            b.show()
-
+    uploader = "show"
 elif "GITHUB_ACTIONS" in os.environ:
-    HAS_UPLOADER = True
-
-    class test_image_results:
-        @staticmethod
-        def upload(a, b):
-            dir_errors = os.path.join(os.path.dirname(__file__), "errors")
-            os.makedirs(dir_errors, exist_ok=True)
-            tmpdir = tempfile.mkdtemp(dir=dir_errors)
-            a.save(os.path.join(tmpdir, "a.png"))
-            b.save(os.path.join(tmpdir, "b.png"))
-            return tmpdir
-
+    uploader = "github_actions"
 else:
     try:
         import test_image_results
 
-        HAS_UPLOADER = True
+        uploader = "aws"
     except ImportError:
         pass
 
 
-def convert_to_comparable(a, b):
+def upload(a: Image.Image, b: Image.Image) -> str | None:
+    if uploader == "show":
+        # local img.show for errors.
+        a.show()
+        b.show()
+    elif uploader == "github_actions":
+        dir_errors = os.path.join(os.path.dirname(__file__), "errors")
+        os.makedirs(dir_errors, exist_ok=True)
+        tmpdir = tempfile.mkdtemp(dir=dir_errors)
+        a.save(os.path.join(tmpdir, "a.png"))
+        b.save(os.path.join(tmpdir, "b.png"))
+        return tmpdir
+    elif uploader == "aws":
+        return test_image_results.upload(a, b)
+    return None
+
+
+def convert_to_comparable(
+    a: Image.Image, b: Image.Image
+) -> tuple[Image.Image, Image.Image]:
     new_a, new_b = a, b
     if a.mode == "P":
         new_a = Image.new("L", a.size)
@@ -67,14 +66,18 @@
     return new_a, new_b
 
 
-def assert_deep_equal(a, b, msg=None):
+def assert_deep_equal(
+    a: Sequence[Any], b: Sequence[Any], msg: str | None = None
+) -> None:
     try:
         assert len(a) == len(b), msg or f"got length {len(a)}, expected {len(b)}"
     except Exception:
         assert a == b, msg
 
 
-def assert_image(im, mode, size, msg=None):
+def assert_image(
+    im: Image.Image, mode: str, size: tuple[int, int], msg: str | None = None
+) -> None:
     if mode is not None:
         assert im.mode == mode, (
             msg or f"got mode {repr(im.mode)}, expected {repr(mode)}"
@@ -86,28 +89,32 @@
         )
 
 
-def assert_image_equal(a, b, msg=None):
+def assert_image_equal(a: Image.Image, b: Image.Image, msg: str | None = None) -> None:
     assert a.mode == b.mode, msg or f"got mode {repr(a.mode)}, expected {repr(b.mode)}"
     assert a.size == b.size, msg or f"got size {repr(a.size)}, expected {repr(b.size)}"
     if a.tobytes() != b.tobytes():
-        if HAS_UPLOADER:
-            try:
-                url = test_image_results.upload(a, b)
+        try:
+            url = upload(a, b)
+            if url:
                 logger.error("URL for test images: %s", url)
-            except Exception:
-                pass
+        except Exception:
+            pass
 
         pytest.fail(msg or "got different content")
 
 
-def assert_image_equal_tofile(a, filename, msg=None, mode=None):
+def assert_image_equal_tofile(
+    a: Image.Image, filename: str, msg: str | None = None, mode: str | None = None
+) -> None:
     with Image.open(filename) as img:
         if mode:
             img = img.convert(mode)
         assert_image_equal(a, img, msg)
 
 
-def assert_image_similar(a, b, epsilon, msg=None):
+def assert_image_similar(
+    a: Image.Image, b: Image.Image, epsilon: float, msg: str | None = None
+) -> None:
     assert a.mode == b.mode, msg or f"got mode {repr(a.mode)}, expected {repr(b.mode)}"
     assert a.size == b.size, msg or f"got size {repr(a.size)}, expected {repr(b.size)}"
 
@@ -125,55 +132,68 @@
             + f" average pixel value difference {ave_diff:.4f} > epsilon {epsilon:.4f}"
         )
     except Exception as e:
-        if HAS_UPLOADER:
-            try:
-                url = test_image_results.upload(a, b)
+        try:
+            url = upload(a, b)
+            if url:
                 logger.exception("URL for test images: %s", url)
-            except Exception:
-                pass
+        except Exception:
+            pass
         raise e
 
 
-def assert_image_similar_tofile(a, filename, epsilon, msg=None, mode=None):
+def assert_image_similar_tofile(
+    a: Image.Image,
+    filename: str,
+    epsilon: float,
+    msg: str | None = None,
+    mode: str | None = None,
+) -> None:
     with Image.open(filename) as img:
         if mode:
             img = img.convert(mode)
         assert_image_similar(a, img, epsilon, msg)
 
 
-def assert_all_same(items, msg=None):
+def assert_all_same(items: Sequence[Any], msg: str | None = None) -> None:
     assert items.count(items[0]) == len(items), msg
 
 
-def assert_not_all_same(items, msg=None):
+def assert_not_all_same(items: Sequence[Any], msg: str | None = None) -> None:
     assert items.count(items[0]) != len(items), msg
 
 
-def assert_tuple_approx_equal(actuals, targets, threshold, msg):
+def assert_tuple_approx_equal(
+    actuals: Sequence[int], targets: tuple[int, ...], threshold: int, msg: str
+) -> None:
     """Tests if actuals has values within threshold from targets"""
-    value = True
     for i, target in enumerate(targets):
-        value *= target - threshold <= actuals[i] <= target + threshold
-
-    assert value, msg + ": " + repr(actuals) + " != " + repr(targets)
+        if not (target - threshold <= actuals[i] <= target + threshold):
+            pytest.fail(msg + ": " + repr(actuals) + " != " + repr(targets))
 
 
 def skip_unless_feature(feature: str) -> pytest.MarkDecorator:
     reason = f"{feature} not available"
     return pytest.mark.skipif(not features.check(feature), reason=reason)
 
 
-def skip_unless_feature_version(feature, version_required, reason=None):
+def skip_unless_feature_version(
+    feature: str, required: str, reason: str | None = None
+) -> pytest.MarkDecorator:
     if not features.check(feature):
         return pytest.mark.skip(f"{feature} not available")
     if reason is None:
-        reason = f"{feature} is older than {version_required}"
-    version_required = parse_version(version_required)
+        reason = f"{feature} is older than {required}"
+    version_required = parse_version(required)
     version_available = parse_version(features.version(feature))
     return pytest.mark.skipif(version_available < version_required, reason=reason)
 
 
-def mark_if_feature_version(mark, feature, version_blacklist, reason=None):
+def mark_if_feature_version(
+    mark: pytest.MarkDecorator,
+    feature: str,
+    version_blacklist: str,
+    reason: str | None = None,
+) -> pytest.MarkDecorator:
     if not features.check(feature):
         return pytest.mark.pil_noop_mark()
     if reason is None:
@@ -194,7 +214,7 @@
     iterations = 100  # count
     mem_limit = 512  # k
 
-    def _get_mem_usage(self):
+    def _get_mem_usage(self) -> float:
         """
         Gets the RUSAGE memory usage, returns in K. Encapsulates the difference
         between macOS and Linux rss reporting
@@ -216,7 +236,7 @@
         #  This is the maximum resident set size used (in kilobytes).
         return mem  # Kb
 
-    def _test_leak(self, core):
+    def _test_leak(self, core: Callable[[], None]) -> None:
         start_mem = self._get_mem_usage()
         for cycle in range(self.iterations):
             core()
@@ -228,17 +248,17 @@
 # helpers
 
 
-def fromstring(data):
+def fromstring(data: bytes) -> Image.Image:
     return Image.open(BytesIO(data))
 
 
-def tostring(im, string_format, **options):
+def tostring(im: Image.Image, string_format: str, **options: dict[str, Any]) -> bytes:
     out = BytesIO()
     im.save(out, string_format, **options)
     return out.getvalue()
 
 
-def hopper(mode=None, cache={}):
+def hopper(mode: str | None = None, cache: dict[str, Image.Image] = {}) -> Image.Image:
     if mode is None:
         # Always return fresh not-yet-loaded version of image.
         # Operations on not-yet-loaded images is separate class of errors
@@ -259,29 +279,31 @@
     return im.copy()
 
 
-def djpeg_available():
+def djpeg_available() -> bool:
     if shutil.which("djpeg"):
         try:
             subprocess.check_call(["djpeg", "-version"])
             return True
         except subprocess.CalledProcessError:  # pragma: no cover
             return False
+    return False
 
 
-def cjpeg_available():
+def cjpeg_available() -> bool:
     if shutil.which("cjpeg"):
         try:
             subprocess.check_call(["cjpeg", "-version"])
             return True
         except subprocess.CalledProcessError:  # pragma: no cover
             return False
+    return False
 
 
-def netpbm_available():
+def netpbm_available() -> bool:
     return bool(shutil.which("ppmquant") and shutil.which("ppmtogif"))
 
 
-def magick_command():
+def magick_command() -> list[str] | None:
     if sys.platform == "win32":
         magickhome = os.environ.get("MAGICK_HOME")
         if magickhome:
@@ -298,47 +320,48 @@
         return imagemagick
     if graphicsmagick and shutil.which(graphicsmagick[0]):
         return graphicsmagick
+    return None
 
 
-def on_appveyor():
+def on_appveyor() -> bool:
     return "APPVEYOR" in os.environ
 
 
-def on_github_actions():
+def on_github_actions() -> bool:
     return "GITHUB_ACTIONS" in os.environ
 
 
-def on_ci():
+def on_ci() -> bool:
     # GitHub Actions and AppVeyor have "CI"
     return "CI" in os.environ
 
 
-def is_big_endian():
+def is_big_endian() -> bool:
     return sys.byteorder == "big"
 
 
-def is_ppc64le():
+def is_ppc64le() -> bool:
     import platform
 
     return platform.machine() == "ppc64le"
 
 
-def is_win32():
+def is_win32() -> bool:
     return sys.platform.startswith("win32")
 
 
-def is_pypy():
+def is_pypy() -> bool:
     return hasattr(sys, "pypy_translation_info")
 
 
-def is_mingw():
+def is_mingw() -> bool:
     return sysconfig.get_platform() == "mingw"
 
 
 class CachedProperty:
-    def __init__(self, func):
+    def __init__(self, func: Callable[[Any], None]) -> None:
         self.func = func
 
-    def __get__(self, instance, cls=None):
+    def __get__(self, instance: Any, cls: type[Any] | None = None) -> Any:
         result = instance.__dict__[self.func.__name__] = self.func(instance)
         return result