All reports of debian-tests-control-uses-national-encoding for the archive. The extended description of this tag is:

The debian/tests/control file should be valid UTF-8, an encoding of the Unicode character set.

There are many ways to convert a file from an encoding like ISO-8859-1; you may for example use "iconv" like:

     $ iconv -f ISO-8859-1 -t UTF-8 file >
     $ mv file

Severity: normal, Certainty: certain

Check: testsuite, Type: source

This tag has not been emitted in any package tested by Lintian.