Add new tests, example scripts, and test improvements

- Add test/test_feature_flags.py (test rawpy.flags dict)
- Add test/test_examples.py (run example scripts as subprocess)
- Add test/test_user_cblack.py regression test for color balance
- Improve test_basic.py: X3F skip helper, assertion improvements
- Add examples/basic_process.py
- Add examples/bad_pixel_repair.py
- Add examples/thumbnail_extract.py

Author: letmaik

examples/bad_pixel_repair.py

@@ -0,0 +1,63 @@
+"""
+Bad Pixel Repair Example
+
+Demonstrates:
+- Using rawpy.enhance module for bad pixel detection/repair
+- Loading pre-computed bad pixel coordinates
+- Repairing bad pixels using median interpolation
+
+Note: In practice, you would first detect bad pixels using:
+    bad_pixels = rawpy.enhance.find_bad_pixels(['image1.NEF', 'image2.NEF', ...])
+
+Usage:
+    python examples/bad_pixel_repair.py
+"""
+
+import numpy as np
+import rawpy
+import rawpy.enhance
+import imageio.v3 as iio
+import os
+import sys
+import tempfile
+
+SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
+REPO_ROOT = os.path.dirname(SCRIPT_DIR)
+TEST_IMAGE = os.path.join(REPO_ROOT, "test", "iss030e122639.NEF")
+BAD_PIXELS_FILE = os.path.join(REPO_ROOT, "test", "bad_pixels.gz")
+
+
+def main():
+    if not os.path.exists(TEST_IMAGE):
+        print(f"Error: Test image not found at {TEST_IMAGE}")
+        return 1
+
+    # Load bad pixel coordinates (if available)
+    if not os.path.exists(BAD_PIXELS_FILE):
+        print(f"Bad pixel file not found: {BAD_PIXELS_FILE}")
+        print("Skipping repair demo. In practice, you would run:")
+        print("  bad_pixels = rawpy.enhance.find_bad_pixels([...image paths...])")
+        return 0
+
+    bad_pixels = np.loadtxt(BAD_PIXELS_FILE, dtype=int)
+
+    print(f"Loaded {len(bad_pixels)} bad pixel coordinates")
+    print(f"Processing: {TEST_IMAGE}")
+
+    with rawpy.imread(TEST_IMAGE) as raw:
+        # Repair bad pixels in-place before postprocessing
+        rawpy.enhance.repair_bad_pixels(raw, bad_pixels, method="median")
+
+        # Now postprocess the repaired data
+        rgb = raw.postprocess()
+
+        output_path = os.path.join(tempfile.gettempdir(), "rawpy_repaired.tiff")
+        iio.imwrite(output_path, rgb)
+        print(f"Saved repaired image to: {output_path}")
+
+    print("Done!")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())

examples/basic_process.py

@@ -0,0 +1,51 @@
+"""
+Basic RAW Processing Example
+
+Demonstrates:
+- Loading a RAW file with rawpy.imread()
+- Converting to RGB with postprocess()
+- Saving the result
+
+Usage:
+    python examples/basic_process.py
+"""
+
+import rawpy
+import imageio.v3 as iio
+import os
+import sys
+import tempfile
+
+# Locate test image (works from repo root or examples/ directory)
+SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
+REPO_ROOT = os.path.dirname(SCRIPT_DIR)
+TEST_IMAGE = os.path.join(REPO_ROOT, "test", "iss030e122639.NEF")
+
+
+def main():
+    if not os.path.exists(TEST_IMAGE):
+        print(f"Error: Test image not found at {TEST_IMAGE}")
+        print("This example requires the test data from the repository.")
+        return 1
+
+    print(f"Loading: {TEST_IMAGE}")
+
+    with rawpy.imread(TEST_IMAGE) as raw:
+        print(f"  Raw type: {raw.raw_type}")
+        print(f"  Image size: {raw.sizes.width}x{raw.sizes.height}")
+
+        # Convert RAW to RGB using default parameters
+        rgb = raw.postprocess()
+        print(f"  Output shape: {rgb.shape}")
+
+        # Save to temp directory (avoids polluting repo)
+        output_path = os.path.join(tempfile.gettempdir(), "rawpy_basic_output.tiff")
+        iio.imwrite(output_path, rgb)
+        print(f"  Saved to: {output_path}")
+
+    print("Done!")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())

examples/thumbnail_extract.py

@@ -0,0 +1,61 @@
+"""
+Thumbnail Extraction Example
+
+Demonstrates:
+- Extracting embedded JPEG thumbnails from RAW files
+- Handling different thumbnail formats (JPEG vs BITMAP)
+- Error handling for missing/unsupported thumbnails
+
+Usage:
+    python examples/thumbnail_extract.py
+"""
+
+import rawpy
+import imageio.v3 as iio
+import os
+import sys
+import tempfile
+
+SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
+REPO_ROOT = os.path.dirname(SCRIPT_DIR)
+TEST_IMAGE = os.path.join(REPO_ROOT, "test", "iss030e122639.NEF")
+
+
+def main():
+    if not os.path.exists(TEST_IMAGE):
+        print(f"Error: Test image not found at {TEST_IMAGE}")
+        return 1
+
+    print(f"Extracting thumbnail from: {TEST_IMAGE}")
+
+    with rawpy.imread(TEST_IMAGE) as raw:
+        try:
+            thumb = raw.extract_thumb()
+        except rawpy.LibRawNoThumbnailError:
+            print("No thumbnail embedded in this file.")
+            return 0
+        except rawpy.LibRawUnsupportedThumbnailError:
+            print("Thumbnail format not supported.")
+            return 0
+
+        print(f"  Thumbnail format: {thumb.format}")
+
+        output_dir = tempfile.gettempdir()
+
+        if thumb.format == rawpy.ThumbFormat.JPEG:
+            output_path = os.path.join(output_dir, "rawpy_thumb.jpg")
+            with open(output_path, "wb") as f:
+                f.write(thumb.data)
+            print(f"  Saved JPEG to: {output_path}")
+
+        elif thumb.format == rawpy.ThumbFormat.BITMAP:
+            output_path = os.path.join(output_dir, "rawpy_thumb.tiff")
+            iio.imwrite(output_path, thumb.data)
+            print(f"  Saved TIFF to: {output_path}")
+
+    print("Done!")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())

test/test_basic.py

@@ -16,6 +16,14 @@
 
 thisDir = os.path.dirname(__file__)
 
+_x3f_supported = rawpy.flags is not None and rawpy.flags.get("X3FTOOLS", False)
+
+def _open_x3f():
+    """Open X3F test file, skip test if format not supported by this LibRaw build."""
+    if not _x3f_supported:
+        pytest.skip("X3F format not supported by this LibRaw build")
+    return rawpy.imread(raw4TestPath)
+
 # Nikon D3S
 rawTestPath = os.path.join(thisDir, 'iss030e122639.NEF')
 badPixelsTestPath = os.path.join(thisDir, 'bad_pixels.gz')
@@ -73,7 +81,7 @@ def testFileOpenAndPostProcess():
     iio.imwrite('test_16daylight_linear.tiff', rgb)
 
 def testFoveonFileOpenAndPostProcess():
-    raw = rawpy.imread(raw4TestPath)
+    raw = _open_x3f()
 
     assert_array_equal(raw.raw_image.shape, [1531, 2304, 3])
     iio.imwrite('test_foveon_raw.tiff', raw.raw_image)
@@ -145,7 +153,7 @@ def testThumbExtractJPEG():
     assert_array_equal(img.shape, [2832, 4256, 3])
 
 def testThumbExtractBitmap():
-    with rawpy.imread(raw4TestPath) as raw:
+    with _open_x3f() as raw:
         thumb = raw.extract_thumb()
     assert thumb.format == rawpy.ThumbFormat.BITMAP
     assert isinstance(thumb.data, np.ndarray)
@@ -171,11 +179,13 @@ def testBayerPattern():
     for path in [rawTestPath, raw2TestPath]:
         raw = rawpy.imread(path)
         assert_equal(raw.color_desc, expected_desc)
-        assert_array_equal(raw.raw_pattern, [[0,1],[3,2]])
+        assert raw.raw_pattern is not None
+        assert_array_equal(raw.raw_pattern, np.array([[0,1],[3,2]], dtype=np.uint8))
 
     raw = rawpy.imread(raw3TestPath)
     assert_equal(raw.color_desc, expected_desc)
-    assert_array_equal(raw.raw_pattern, [[3,2],[0,1]])
+    assert raw.raw_pattern is not None
+    assert_array_equal(raw.raw_pattern, np.array([[3,2],[0,1]], dtype=np.uint8))
 
 def testAutoWhiteBalance():
     # Test that auto_whitebalance returns None before postprocessing
@@ -281,7 +291,7 @@ def testCropSizeCanon():
         assert_equal(s.crop_height, 3744)
 
 def testCropSizeSigma():
-    with rawpy.imread(raw4TestPath) as raw:
+    with _open_x3f() as raw:
         s = raw.sizes
         assert_equal(s.crop_left_margin, 0)
         assert_equal(s.crop_top_margin, 0)

test/test_examples.py

@@ -0,0 +1,56 @@
+"""
+Test that example scripts run without errors.
+
+Each example is executed as a subprocess so it runs exactly as a user would.
+"""
+
+import os
+import subprocess
+import sys
+
+import pytest
+
+REPO_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+EXAMPLES_DIR = os.path.join(REPO_ROOT, "examples")
+TEST_IMAGE = os.path.join(REPO_ROOT, "test", "iss030e122639.NEF")
+
+needs_test_image = pytest.mark.skipif(
+    not os.path.exists(TEST_IMAGE),
+    reason="test image not available",
+)
+
+skip_examples = pytest.mark.skipif(
+    os.environ.get("RAWPY_SKIP_EXAMPLES", "") == "1",
+    reason="RAWPY_SKIP_EXAMPLES is set (e.g., slow QEMU emulation)",
+)
+
+pytestmark = skip_examples
+
+
+def run_example(script_name: str) -> subprocess.CompletedProcess:
+    """Run an example script and return the result."""
+    script_path = os.path.join(EXAMPLES_DIR, script_name)
+    return subprocess.run(
+        [sys.executable, script_path],
+        capture_output=True,
+        text=True,
+        timeout=120,
+    )
+
+
+@needs_test_image
+def test_basic_process():
+    result = run_example("basic_process.py")
+    assert result.returncode == 0, result.stderr
+
+
+@needs_test_image
+def test_thumbnail_extract():
+    result = run_example("thumbnail_extract.py")
+    assert result.returncode == 0, result.stderr
+
+
+@needs_test_image
+def test_bad_pixel_repair():
+    result = run_example("bad_pixel_repair.py")
+    assert result.returncode == 0, result.stderr