Error on output for `humann2_split_table`

[theymard1]

Linting tool galaxytools/tools/humann2/humann2_split_table.xml
Applying linter tests... WARNING
    .. WARNING: No outputs or expectations defined for tests, this test is likely invalid.
    .. WARNING: No valid test(s) found.
Applying linter output... WARNING
    .. WARNING: Unknown element found in outputs [outputs]