c962c70 testlib: Fix SyntaxWarning "is" with a literal

1 file Authored by lslebodn 4 years ago, Committed by pbrezina 4 years ago,
    testlib: Fix SyntaxWarning "is" with a literal
    
    Reviewed-by: Pavel Březina <pbrezina@redhat.com>\
    
    Reviewed-by: Tomáš Halman <thalman@redhat.com>