output_collection file comparison is seemingly ignored

[bernt-matthias]

I have a tool with a test like:

        <test>
...
            <output_collection name="bams" type="list" count="2">
                <element name="PopA_01.matches" file="tsv2bam/PopA_01.matches.bam" ftype="bam" compare="sim_size"/>
                <element name="PopA_02.matches" file="tsv2bam/PopA_02.matches.bam" ftype="bam" compare="sim_size"  />
	    </output_collection>
        </test>

irrespective of the content of the the bam files the test is successful. Same if compare="diff".

The <element> are not completely ignored: if I give a wrong file name the test fails.