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.
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=40448a023600b7b5e876d0a1d2a25878e61de579'>refs</a><a class='active' href='/guix/log/po/packages/hu.po'>log</a><a href='/guix/tree/po/packages/hu.po?id=40448a023600b7b5e876d0a1d2a25878e61de579'>tree</a><a href='/guix/commit/po/packages/hu.po?id=40448a023600b7b5e876d0a1d2a25878e61de579'>commit</a><a href='/guix/diff/po/packages/hu.po?id=40448a023600b7b5e876d0a1d2a25878e61de579'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/po/packages/hu.po'>
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<div class='path'>path: <a href='/guix/log/?id=40448a023600b7b5e876d0a1d2a25878e61de579'>root</a>/<a href='/guix/log/po?id=40448a023600b7b5e876d0a1d2a25878e61de579'>po</a>/<a href='/guix/log/po/packages?id=40448a023600b7b5e876d0a1d2a25878e61de579'>packages</a>/<a href='/guix/log/po/packages/hu.po?id=40448a023600b7b5e876d0a1d2a25878e61de579'>hu.po</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/po/packages/hu.po?id=40448a023600b7b5e876d0a1d2a25878e61de579&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2018-01-17 17:15:55 -0800'>2018-01-17</span></td><td><a href='/guix/commit/po/packages/hu.po?id=d86db8d5625f3cbc1061e8d9c115bd42821728a5'>nls: Update 'hu' translation.</a></td><td>Leo Famulari</td></tr>
<tr><td><span title='2017-12-18 11:12:41 +0100'>2017-12-18</span></td><td><a href='/guix/commit/po/packages/hu.po?id=44233027243700e8a5a973149d51392262bd9833'>nls: Update 'hu' translation.</a></td><td>Ludovic Courtès</td></tr>