tests/test-check-config.t

run-tests: fix `HGTESTEXTRAEXTENSIONS` with py3

Since `extensions` was a str and `section` bytes, it never populated anything.
If it had, it would have put bytes into the environment dictionary that is all
str.  As everything starts and ends as str, remove the incomplete attempt at
byteification.  It doesn't appear that we had any test coverage of this bit of
code, so also add a non-extension config to make sure it is filtered out
properly.

Differential Revision: https://phab.mercurial-scm.org/D9557

#require test-repo

  $ . "$TESTDIR/helpers-testrepo.sh"

Sanity check check-config.py

  $ cat > testfile.py << EOF
  > # Good
  > foo = ui.config('ui', 'username')
  > # Missing
  > foo = ui.config('ui', 'doesnotexist')
  > # Missing different type
  > foo = ui.configint('ui', 'missingint')
  > # Missing with default value
  > foo = ui.configbool('ui', 'missingbool1', default=True)
  > foo = ui.configbool('ui', 'missingbool2', False)
  > # Inconsistent values for defaults.
  > foo = ui.configint('ui', 'intdefault', default=1)
  > foo = ui.configint('ui', 'intdefault', default=42)
  > # Can suppress inconsistent value error
  > foo = ui.configint('ui', 'intdefault2', default=1)
  > # inconsistent config: ui.intdefault2
  > foo = ui.configint('ui', 'intdefault2', default=42)
  > EOF

  $ cat > files << EOF
  > mercurial/helptext/config.txt
  > $TESTTMP/testfile.py
  > EOF

  $ cd "$TESTDIR"/..

  $ "$PYTHON" contrib/check-config.py < $TESTTMP/files
  foo = ui.configint('ui', 'intdefault', default=42)
  conflict on ui.intdefault: ('int', '42') != ('int', '1')
  at $TESTTMP/testfile.py:12:
  undocumented: ui.doesnotexist (str)
  undocumented: ui.intdefault (int) [42]
  undocumented: ui.intdefault2 (int) [42]
  undocumented: ui.missingbool1 (bool) [True]
  undocumented: ui.missingbool2 (bool)
  undocumented: ui.missingint (int)

New errors are not allowed. Warnings are strongly discouraged.

  $ testrepohg files "set:(**.py or **.txt) - tests/**" | sed 's|\\|/|g' |
  >   "$PYTHON" contrib/check-config.py