Fix size detection

Author: ewjoachim

tests/roots/test-custom-social-card-generation/conf.py

@@ -0,0 +1,28 @@
+from __future__ import annotations
+
+import io
+import pathlib
+
+extensions = ['sphinxext.opengraph']
+
+master_doc = 'index'
+exclude_patterns = ['_build']
+
+html_theme = 'basic'
+
+ogp_site_url = 'http://example.org/en/latest/'
+
+
+def setup(app):
+    app.connect('generate-social-card', generate)
+
+
+def generate(
+    app,
+    contents,
+    check_if_signature_exists,
+) -> None | tuple[io.BytesIO, str]:
+    signature = 'custom-signature'
+    check_if_signature_exists(signature)
+
+    return io.BytesIO(pathlib.Path(app.srcdir / 'pixel.png').read_bytes()), signature

tests/roots/test-custom-social-card-generation/index.rst

@@ -0,0 +1 @@
+Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse at lorem ornare, fringilla massa nec, venenatis mi. Donec erat sapien, tincidunt nec rhoncus nec, scelerisque id diam. Orci varius natoque penatibus et magnis dis parturient mauris.

tests/roots/test-custom-social-card-generation/pixel.png

@@ -119,7 +119,7 @@ def test_image_alt(og_meta_tags):
 
 
 @pytest.mark.sphinx('html', testroot='simple')
-def test_image_social_cards(meta_tags):
+def test_image_social_cards(content, meta_tags):
     """Social cards should automatically be added if no og:image is given."""
     pytest.importorskip('matplotlib')
     # Asserting `in` instead of `==` because of the hash that is generated
@@ -136,6 +136,33 @@ def test_image_social_cards(meta_tags):
     assert 'summary_large_image' in get_tag_content(
         meta_tags, 'card', kind='name', prefix='twitter'
     )
+    png_file = content.outdir / get_tag_content(meta_tags, 'image').split('/', 5)[-1]
+    assert png_file.is_file()
+    # https://en.wikipedia.org/wiki/List_of_file_signatures
+    assert png_file.read_bytes()[:8] == b'\x89PNG\r\n\x1a\n'
+    assert get_tag_content(meta_tags, 'image:width') == '1146'
+    assert get_tag_content(meta_tags, 'image:height') == '600'
+
+
+@pytest.mark.sphinx('html', testroot='custom-social-card-generation')
+def test_image_social_cards_custom(content, meta_tags):
+    """Providing a custom generation function for social cards."""
+    # Asserting `in` instead of `==` because of the hash that is generated
+    assert (
+        'http://example.org/en/latest/_images/social_previews/summary_index'
+        in get_tag_content(meta_tags, 'image')
+    )
+    # Make sure the extra tags are in the HTML
+    assert 'summary_large_image' in get_tag_content(
+        meta_tags, 'card', kind='name', prefix='twitter'
+    )
+    assert get_tag_content(meta_tags, 'image:width') == '1'
+    assert get_tag_content(meta_tags, 'image:height') == '1'
+    png_file = content.outdir / get_tag_content(meta_tags, 'image').split('/', 5)[-1]
+    assert png_file.is_file()
+    # https://en.wikipedia.org/wiki/List_of_file_signatures
+    assert png_file.read_bytes()[:8] == b'\x89PNG\r\n\x1a\n'
+    assert len(png_file.read_bytes()) == 95  # Size of the provided pixel.png
 
 
 @pytest.mark.sphinx('html', testroot='type')