Add tests for SEO meta tags rendering and improve meta_tags.html formatting

config/tests/test_seo.py

@@ -0,0 +1,106 @@
+import re
+from typing import TYPE_CHECKING
+
+from django.template.loader import render_to_string
+from django.test import RequestFactory
+
+if TYPE_CHECKING:
+    from django.core.handlers.wsgi import WSGIRequest
+
+
+def _render_meta_tags(context: dict | None = None, path: str = "/test/") -> str:
+    """Helper function to render meta tags template with a test request and given context.
+
+    Args:
+        context: Optional dictionary of context variables to pass to the template.
+        path: The URL path for the test request.
+
+    Returns:
+        The rendered HTML content of the meta tags.
+    """
+    request: WSGIRequest = RequestFactory().get(path)
+    return render_to_string(
+        "includes/meta_tags.html",
+        context=context or {},
+        request=request,
+    )
+
+
+def _extract_meta_content(content: str, key: str) -> str:
+    """Extract the content of a meta tag by its name or property.
+
+    Args:
+        content: The full HTML content to search within.
+        key: The value of the name or property attribute to match.
+
+    Returns:
+        The content attribute value of the matched meta tag.
+    """
+    pattern: re.Pattern[str] = re.compile(
+        rf'<meta\s+(?:name|property)="{re.escape(key)}"\s+content="([^"]*)"\s*/?>',
+    )
+    match: re.Match[str] | None = pattern.search(content)
+    assert match is not None, f"Expected meta tag for {key!r} in rendered output."
+    return match.group(1)
+
+
+def test_meta_tags_use_request_absolute_url_for_og_url_and_canonical() -> None:
+    """Test that without page_url in context, og:url and canonical tags use request.build_absolute_uri."""
+    content: str = _render_meta_tags(path="/drops/")
+
+    assert _extract_meta_content(content, "og:url") == "http://testserver/drops/"
+    assert '<link rel="canonical" href="http://testserver/drops/" />' in content
+
+
+def test_meta_tags_use_explicit_page_url_for_og_url_and_canonical() -> None:
+    """Test that providing page_url in context results in correct og:url and canonical tags."""
+    content: str = _render_meta_tags(
+        {
+            "page_url": "https://example.com/custom-page/",
+        },
+        path="/ignored/",
+    )
+
+    assert (
+        _extract_meta_content(content, "og:url") == "https://example.com/custom-page/"
+    )
+    assert '<link rel="canonical" href="https://example.com/custom-page/" />' in content
+
+
+def test_meta_tags_twitter_card_is_summary_without_image() -> None:
+    """Test that without page_image in context, twitter:card is summary and no twitter:image tag is present."""
+    content: str = _render_meta_tags()
+
+    assert _extract_meta_content(content, "twitter:card") == "summary"
+    assert 'name="twitter:image"' not in content
+
+
+def test_meta_tags_twitter_card_is_summary_large_image_with_page_image() -> None:
+    """Test that providing page_image in context results in twitter:card being summary_large_image and correct og:image and twitter:image tags."""
+    content: str = _render_meta_tags({
+        "page_image": "https://example.com/image.png",
+        "page_image_width": 1200,
+        "page_image_height": 630,
+    })
+
+    assert _extract_meta_content(content, "twitter:card") == "summary_large_image"
+    assert _extract_meta_content(content, "og:image") == "https://example.com/image.png"
+    assert (
+        _extract_meta_content(content, "twitter:image")
+        == "https://example.com/image.png"
+    )
+    assert _extract_meta_content(content, "og:image:width") == "1200"
+    assert _extract_meta_content(content, "og:image:height") == "630"
+
+
+def test_meta_tags_render_pagination_links() -> None:
+    """Test that pagination_info in context results in correct prev/next link tags in output."""
+    content: str = _render_meta_tags({
+        "pagination_info": [
+            {"rel": "prev", "url": "https://example.com/page/1/"},
+            {"rel": "next", "url": "https://example.com/page/3/"},
+        ],
+    })
+
+    assert '<link rel="prev" href="https://example.com/page/1/" />' in content
+    assert '<link rel="next" href="https://example.com/page/3/" />' in content