Use context managers to ensure Pillow images are closed

tests/test_lept.py

@@ -38,7 +38,8 @@ def test_colormap_backgroundnorm(resources):
 def crom_pix(resources):
     pix = lept.Pix.open(resources / 'crom.png')
     im = Image.open(resources / 'crom.png')
-    return pix, im
+    yield pix, im
+    im.close()
 
 
 def test_pix_basic(crom_pix):

tests/test_main.py

@@ -118,8 +118,8 @@ def test_deskew(spoof_tesseract_noop, resources, outdir):
 
 def test_remove_background(spoof_tesseract_noop, resources, outdir):
     # Ensure the input image does not contain pure white/black
-    im = Image.open(resources / 'congress.jpg')
-    assert im.getextrema() != ((0, 255), (0, 255), (0, 255))
+    with Image.open(resources / 'congress.jpg') as im:
+        assert im.getextrema() != ((0, 255), (0, 255), (0, 255))
 
     output_pdf = check_ocrmypdf(
         resources / 'congress.jpg',
@@ -145,8 +145,8 @@ def test_remove_background(spoof_tesseract_noop, resources, outdir):
     )
 
     # The output image should contain pure white and black
-    im = Image.open(output_png)
-    assert im.getextrema() == ((0, 255), (0, 255), (0, 255))
+    with Image.open(output_png) as im:
+        assert im.getextrema() == ((0, 255), (0, 255), (0, 255))
 
 
 # This will run 5 * 2 * 2 = 20 test cases
@@ -792,6 +792,7 @@ def test_compression_preserved(
         assert pdfimage.color == Colorspace.rgb, "Colorspace changed"
     elif im.mode.startswith('L'):
         assert pdfimage.color == Colorspace.gray, "Colorspace changed"
+    im.close()
 
 
 @pytest.mark.parametrize(
@@ -853,6 +854,7 @@ def test_compression_changed(
         assert pdfimage.color == Colorspace.rgb, "Colorspace changed"
     elif im.mode.startswith('L'):
         assert pdfimage.color == Colorspace.gray, "Colorspace changed"
+    im.close()
 
 
 def test_sidecar_pagecount(spoof_tesseract_cache, resources, outpdf):

tests/test_optimize.py

@@ -51,8 +51,8 @@ def test_mono_not_inverted(resources, outdir):
         log=logging.getLogger(name='test_mono_not_inverted'),
     )
 
-    im = Image.open(fspath(outdir / 'im.png'))
-    assert im.getpixel((0, 0)) == 255, "Expected white background"
+    with Image.open(fspath(outdir / 'im.png')) as im:
+        assert im.getpixel((0, 0)) == 255, "Expected white background"
 
 
 @pytest.mark.skipif(not pngquant.available(), reason='need pngquant')
@@ -110,10 +110,10 @@ def test_flate_to_jbig2(resources, outdir, spoof_tesseract_noop):
     # This test requires an image that pngquant is capable of converting to
     # to 1bpp - so use an existing 1bpp image, convert up, confirm it can
     # convert down
-    im = Image.open(fspath(resources / 'typewriter.png'))
-    assert im.mode in ('1', 'P')
-    im = im.convert('L')
-    im.save(fspath(outdir / 'type8.png'))
+    with Image.open(fspath(resources / 'typewriter.png')) as im:
+        assert im.mode in ('1', 'P')
+        im = im.convert('L')
+        im.save(fspath(outdir / 'type8.png'))
 
     check_ocrmypdf(
         outdir / 'type8.png',

tests/test_rotation.py

@@ -224,12 +224,12 @@ def test_rotate_deskew_timeout(resources, outdir):
 @pytest.mark.parametrize('image_angle', (0, 90, 180, 270))
 def test_rotate_page_level(image_angle, page_angle, resources, outdir):
     def make_rotate_test(prefix, image_angle, page_angle):
-        im = Image.open(fspath(resources / 'typewriter.png'))
-        if image_angle != 0:
-            ccw_angle = -image_angle % 360
-            im = im.transpose(getattr(Image, f'ROTATE_{ccw_angle}'))
         memimg = BytesIO()
-        im.save(memimg, format='PNG')
+        with Image.open(fspath(resources / 'typewriter.png')) as im:
+            if image_angle != 0:
+                ccw_angle = -image_angle % 360
+                im = im.transpose(getattr(Image, f'ROTATE_{ccw_angle}'))
+            im.save(memimg, format='PNG')
         memimg.seek(0)
         mempdf = BytesIO()
         img2pdf.convert(