This test fails because it expects a MIME type "Content-Type: image/gif"
whereas that provided by libmagic is "Content-Type: image/gif; charset=binary"
Presumably the test was written against a different version.
--- aegis-4.24/test/02/t0228a-matt.sh	2008-03-14 07:19:27.000000000 +0100
+++ aegis-4.24/test/02/t0228a-matt.sh	2014-01-27 09:43:44.000000000 +0100
@@ -147,7 +147,8 @@
 SCRIPT_NAME=/cgi-bin/aeget \
 PATH_INFO=icon/rss.gif \
 QUERY_STRING= \
-$bin/aeget > rss.served.gif 2>&1
+$bin/aeget \
+| sed -e 's%^Content-Type: image/gif; charset=binary%Content-Type: image/gif%' > rss.served.gif 2>&1
 if test $? -ne 0 ; then fail; fi
 
 # Compare the expected and the actual received file.
e='h' onchange='this.form.submit();'>
<option value='koszko' selected='selected'>koszko</option>
<option value='koszko-scripts'>koszko-scripts</option>
</select> <input type='submit' value='switch'/></form></td></tr>
<tr><td class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
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<a href='/guix/about/'>about</a><a href='/guix/'>summary</a><a href='/guix/refs/?id=f7d88cd4707eeaf02f9b854f05803d8d0428f670'>refs</a><a class='active' href='/guix/log/tests/ed25519bis.key'>log</a><a href='/guix/tree/tests/ed25519bis.key?id=f7d88cd4707eeaf02f9b854f05803d8d0428f670'>tree</a><a href='/guix/commit/tests/ed25519bis.key?id=f7d88cd4707eeaf02f9b854f05803d8d0428f670'>commit</a><a href='/guix/diff/tests/ed25519bis.key?id=f7d88cd4707eeaf02f9b854f05803d8d0428f670'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/tests/ed25519bis.key'>
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<div class='path'>path: <a href='/guix/log/?id=f7d88cd4707eeaf02f9b854f05803d8d0428f670'>root</a>/<a href='/guix/log/tests?id=f7d88cd4707eeaf02f9b854f05803d8d0428f670'>tests</a>/<a href='/guix/log/tests/ed25519bis.key?id=f7d88cd4707eeaf02f9b854f05803d8d0428f670'>ed25519bis.key</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/tests/ed25519bis.key?id=f7d88cd4707eeaf02f9b854f05803d8d0428f670&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-06-05 22:54:06 +0200'>2020-06-05</span></td><td><a href='/guix/commit/tests/ed25519bis.key?id=c83eedba2361c3831d3efb5ad63d5077d636fb28'>git-authenticate: Add tests.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/tests/git.scm (call-with-environment-variables)
(with-environment-variables): Remove.
* guix/tests/git.scm (populate-git-repository): Add clauses for signed
commits and signed merges.
* guix/tests/gnupg.scm: New file.
* tests/git-authenticate.scm: New file.
* tests/ed25519bis.key, tests/ed25519bis.sec: New files.
* Makefile.am (dist_noinst_DATA): Add 'guix/tests/gnupg.scm'.
(SCM_TESTS): Add 'tests/git-authenticate.scm'.
(EXTRA_DIST): Add tests/ed25519bis.{key,sec}.
</span></span></td><td>Ludovic Courtès</td></tr>