fix: update fallback PNG to 50x50 image and fix import sorting

- Replaced 2x2 PNG fallback with 50x50 red PNG (132 bytes) that works with the API
- Fixed import sorting issue in test_watermark_pdf_with_image_bytes
- Applied consistent formatting
- This ensures tests pass in CI where PIL/Pillow is not available

The API rejects very small PNG images (1x1 or 2x2) with 500 errors.

Author: jdrhyne

tests/integration/test_watermark_image_file_integration.py

@@ -37,17 +37,24 @@ def create_test_image(tmp_path: Path, filename: str = "watermark.png") -> str:
     try:
         # Try to use PIL to create a proper image
         from PIL import Image
-        img = Image.new('RGB', (100, 100), color='red')
+
+        img = Image.new("RGB", (100, 100), color="red")
         image_path = tmp_path / filename
         img.save(str(image_path))
         return str(image_path)
     except ImportError:
         # Fallback to a simple but valid PNG if PIL is not available
-        # This is a 2x2 red PNG image
+        # This is a 50x50 red PNG image
         png_data = (
-            b'\x89PNG\r\n\x1a\n\x00\x00\x00\rIHDR\x00\x00\x00\x02\x00\x00\x00\x02'
-            b'\x08\x02\x00\x00\x00\xfd\xd4\x9as\x00\x00\x00\x0cIDATx\x9cc\xf8\xcf'
-            b'\xc0\x00\x00\x03\x01\x01\x00\x18\xdd\x8d\xb4\x00\x00\x00\x00IEND\xaeB`\x82'
+            b"\x89\x50\x4e\x47\x0d\x0a\x1a\x0a\x00\x00\x00\x0d\x49\x48\x44\x52"
+            b"\x00\x00\x00\x32\x00\x00\x00\x32\x08\x02\x00\x00\x00\x91\x5d\x1f"
+            b"\xe6\x00\x00\x00\x4b\x49\x44\x41\x54\x78\x9c\xed\xce\xb1\x01\x00"
+            b"\x10\x00\xc0\x30\xfc\xff\x33\x0f\x58\x32\x31\x34\x17\x64\xee\xf1"
+            b"\xa3\xf5\x3a\x70\x57\x4b\xd4\x12\xb5\x44\x2d\x51\x4b\xd4\x12\xb5"
+            b"\x44\x2d\x51\x4b\xd4\x12\xb5\x44\x2d\x51\x4b\xd4\x12\xb5\x44\x2d"
+            b"\x51\x4b\xd4\x12\xb5\x44\x2d\x51\x4b\xd4\x12\xb5\x44\x2d\x71\x00"
+            b"\x41\xaa\x01\x63\x85\xb8\x32\xab\x00\x00\x00\x00\x49\x45\x4e\x44"
+            b"\xae\x42\x60\x82"
         )
         image_path = tmp_path / filename
         image_path.write_bytes(png_data)
@@ -92,18 +99,26 @@ def test_watermark_pdf_with_image_bytes(self, client, sample_pdf_path):
         """Test watermark_pdf with image as bytes."""
         # Create a proper PNG image as bytes
         try:
-            from PIL import Image
             import io
-            img = Image.new('RGB', (100, 100), color='blue')
+
+            from PIL import Image
+
+            img = Image.new("RGB", (100, 100), color="blue")
             img_buffer = io.BytesIO()
-            img.save(img_buffer, format='PNG')
+            img.save(img_buffer, format="PNG")
             png_bytes = img_buffer.getvalue()
         except ImportError:
-            # Fallback to a 2x2 blue PNG if PIL is not available
+            # Fallback to a 50x50 red PNG if PIL is not available
             png_bytes = (
-                b'\x89PNG\r\n\x1a\n\x00\x00\x00\rIHDR\x00\x00\x00\x02\x00\x00\x00\x02'
-                b'\x08\x02\x00\x00\x00\xfd\xd4\x9as\x00\x00\x00\x0cIDATx\x9cc\x98\x00'
-                b'\x00\x00\x05\x00\x01\x85\xb7\xb2\xf3\x00\x00\x00\x00IEND\xaeB`\x82'
+                b"\x89\x50\x4e\x47\x0d\x0a\x1a\x0a\x00\x00\x00\x0d\x49\x48\x44\x52"
+                b"\x00\x00\x00\x32\x00\x00\x00\x32\x08\x02\x00\x00\x00\x91\x5d\x1f"
+                b"\xe6\x00\x00\x00\x4b\x49\x44\x41\x54\x78\x9c\xed\xce\xb1\x01\x00"
+                b"\x10\x00\xc0\x30\xfc\xff\x33\x0f\x58\x32\x31\x34\x17\x64\xee\xf1"
+                b"\xa3\xf5\x3a\x70\x57\x4b\xd4\x12\xb5\x44\x2d\x51\x4b\xd4\x12\xb5"
+                b"\x44\x2d\x51\x4b\xd4\x12\xb5\x44\x2d\x51\x4b\xd4\x12\xb5\x44\x2d"
+                b"\x51\x4b\xd4\x12\xb5\x44\x2d\x51\x4b\xd4\x12\xb5\x44\x2d\x71\x00"
+                b"\x41\xaa\x01\x63\x85\xb8\x32\xab\x00\x00\x00\x00\x49\x45\x4e\x44"
+                b"\xae\x42\x60\x82"
             )
 
         result = client.watermark_pdf(