diff --git a/test/resources/php-markdown-extra.mdtest/Footnotes.text b/test/resources/php-markdown-extra.mdtest/Footnotes.text
index 95b5ea8..c54e436 100644
--- a/test/resources/php-markdown-extra.mdtest/Footnotes.text
+++ b/test/resources/php-markdown-extra.mdtest/Footnotes.text
@@ -68,3 +68,9 @@ Footnotes mixed with images[^image-mixed]
 [img6]: images/MGR-1800-travel.jpeg "Travel Speeds in 1800"
 [^image-mixed]: Footnote Content
 [img7]: images/MGR-1830-travel.jpeg "Travel Speeds in 1830"
+
+ - - -
+
+This is not a valid footnote name because it has whitespace.[^invalid fn]
+
+[^invalid fn]: an invalid footnote name
diff --git a/test/resources/php-markdown-extra.mdtest/Footnotes.xhtml b/test/resources/php-markdown-extra.mdtest/Footnotes.xhtml
index fe0a464..2e16a92 100644
--- a/test/resources/php-markdown-extra.mdtest/Footnotes.xhtml
+++ b/test/resources/php-markdown-extra.mdtest/Footnotes.xhtml
@@ -30,6 +30,10 @@ footnote test<sup id="fnref:reference"><a href="#fn:reference" class="footnote-r
 
 <p>Footnotes mixed with images<sup id="fnref:image-mixed"><a class="footnote-ref" role="doc-noteref" href="#fn:image-mixed">11</a></sup><img alt="1800 Travel" src="images/MGR-1800-travel.jpeg" title="Travel Speeds in 1800"/><img alt="1830 Travel" src="images/MGR-1830-travel.jpeg" title="Travel Speeds in 1830"/></p>
 
+<hr/>
+
+<p>This is not a valid footnote name because it has whitespace.[^invalid fn]</p>
+
 <div class="footnotes" role="doc-endnotes">
 <hr />
 <ol>