Added default jpeg quality constant, added test

src/groundlight/images.py

@@ -4,6 +4,8 @@
 
 from groundlight.optional_imports import Image, np
 
+DEFAULT_JPEG_QUALITY = 95
+
 
 class ByteStreamWrapper(IOBase):
     """This class acts as a thin wrapper around bytes in order to
@@ -28,11 +30,11 @@ def close(self) -> None:
         pass
 
 
-def bytestream_from_filename(image_filename: str, jpeg_quality) -> ByteStreamWrapper:
+def bytestream_from_filename(image_filename: str, jpeg_quality: int = DEFAULT_JPEG_QUALITY) -> ByteStreamWrapper:
     """Determines what to do with an arbitrary filename
 
     Only supports JPEG and PNG files for now.
-    For PNG files, we convert to a JPEG.
+    For PNG files, we convert to RGB format used in JPEGs.
     """
     if imghdr.what(image_filename) == "jpeg":
         buffer = buffer_from_jpeg_file(image_filename)
@@ -57,7 +59,7 @@ def buffer_from_jpeg_file(image_filename: str) -> BufferedReader:
     raise ValueError("We only support JPEG files, for now.")
 
 
-def jpeg_from_numpy(img: np.ndarray, jpeg_quality: int = 95) -> bytes:
+def jpeg_from_numpy(img: np.ndarray, jpeg_quality: int = DEFAULT_JPEG_QUALITY) -> bytes:
     """Converts a numpy array to BytesIO."""
     pilim = Image.fromarray(img.astype("uint8"), "RGB")
     with BytesIO() as buf:
@@ -66,7 +68,7 @@ def jpeg_from_numpy(img: np.ndarray, jpeg_quality: int = 95) -> bytes:
         return out
 
 
-def bytestream_from_pil(pil_image: Image.Image, jpeg_quality: int = 95) -> ByteStreamWrapper:
+def bytestream_from_pil(pil_image: Image.Image, jpeg_quality: int = DEFAULT_JPEG_QUALITY) -> ByteStreamWrapper:
     """Converts a PIL image to a BytesIO."""
     bytesio = BytesIO()
     pil_image.save(bytesio, "jpeg", quality=jpeg_quality)

test/unit/test_imagefuncs.py

@@ -5,6 +5,7 @@
 from io import BytesIO
 
 import pytest
+import PIL
 from groundlight.images import *
 from groundlight.optional_imports import *
 
@@ -26,6 +27,22 @@ def test_jpeg_from_numpy():
     assert len(jpeg2) > len(jpeg3)
 
 
+def test_bytestream_from_filename():
+    images_streams = []
+    images_streams.append(bytestream_from_filename("test/assets/cat.jpeg"))
+    images_streams.append(bytestream_from_filename("test/assets/cat.png"))
+    images_streams.append(bytestream_from_filename("test/assets/cat.png", jpeg_quality=95))
+    for i in images_streams:
+        assert isinstance(i, ByteStreamWrapper)
+        image = Image.open(i)
+        assert image.mode == "RGB"
+
+    # pixel based test, verified the image is correct by eye, then got a pixel whose value to check against
+    png_bytestream = bytestream_from_filename("test/assets/cat.png", jpeg_quality=95)
+    png_image = Image.open(png_bytestream)
+    assert png_image.getpixel((200, 200)) == (215, 209, 197)
+
+
 def test_unsupported_image_type():
     with pytest.raises(TypeError):
         parse_supported_image_types(1)  # type: ignore