galaxy/test/functional/tools/implicit_conversion_optional_param.xml

<tool id="implicit_conversion_optional_param" name="Test Implicit Conversion" version="0.1" profile="22.01">
    <!-- test that optional parameter in bigwig to wig converter can be left unset -->
    <command><![CDATA[cp '$input' '$output']]></command>
    <inputs>
        <param name="input" type="data" format="wig" label="Biom1 file" />
    </inputs>
    <outputs>
        <data name="output" format="wig" />
    </outputs>
    <tests>
        <!-- bigwig file for wig input triggers bigwig to wig conversion -->
        <test>
            <param name="input" ftype="bigwig" value="2.bigwig" />
            <output name="output" ftype="wig">
                <assert_contents>
                    <has_text text="variableStep chrom" />
                </assert_contents>
            </output>
        </test>
    </tests>
    <help>
    </help>
</tool>