Start of consolidating tests for exceptions

Author: adamtheturtle

tests/test_exceptions/test_image_too_large.py

@@ -2,12 +2,68 @@
 Tests for various exceptions.
 """
 
+import io
+import random
+
 import pytest
+from PIL import Image
 from requests import codes
 
 from vws import VWS
-from vws.exceptions import UnknownTarget
+from vws.exceptions import ImageTooLarge, UnknownTarget
+
+
+def _make_image_file(
+    file_format: str,
+    color_space: str,
+    width: int,
+    height: int,
+) -> io.BytesIO:
+    """
+    Return an image file in the given format and color space.
+
+    The image file is filled with randomly colored pixels.
+
+    Args:
+        file_format: See
+            http://pillow.readthedocs.io/en/3.1.x/handbook/image-file-formats.html
+        color_space: One of "L", "RGB", or "CMYK".
+        width: The width, in pixels of the image.
+        height: The width, in pixels of the image.
+
+    Returns:
+        An image file in the given format and color space.
+    """
+    image_buffer = io.BytesIO()
+    reds = random.choices(population=range(0, 255), k=width * height)
+    greens = random.choices(population=range(0, 255), k=width * height)
+    blues = random.choices(population=range(0, 255), k=width * height)
+    pixels = list(zip(reds, greens, blues))
+    image = Image.new(color_space, (width, height))
+    image.putdata(pixels)
+    image.save(image_buffer, file_format)
+    image_buffer.seek(0)
+    return image_buffer
+
+
+def test_image_too_large(client: VWS) -> None:
+    """
+    When giving an image which is too large, an ``ImageTooLarge`` exception is
+    raised.
+    """
+    width = height = 890
+
+    png_too_large = _make_image_file(
+        file_format='PNG',
+        color_space='RGB',
+        width=width,
+        height=height,
+    )
+
+    with pytest.raises(ImageTooLarge) as exc:
+        client.add_target(name='x', width=1, image=png_too_large)
 
+    assert exc.value.response.status_code == codes.UNPROCESSABLE_ENTITY
 
 def test_invalid_given_id(client: VWS) -> None:
     """