Remove "file" from test/topgm
PATH=${PWD%code*}code:$PATH
python -m pngsuite basi0g04 |
-pripngtopam - | file - | grep -q -i 'netpbm.*gr[ae]ymap'
+pripngtopam - |
+# The last 1024 bytes (32x32) are binary data; extract header
+head -c -1024 | tr -cs 0-9A-Z |
+grep -q 'P5 32 32 15'
