Rudder

The problem is the second test, the difference in the verbose logs:

verbose: Additional promise info: version '1.0' source path '/root/ncf/tests/acceptance/../../tree/20_cfe_basics/ncf_lib.cf' at line 336 comment 'Insert line in section section_test2'
 verbose: The promised end pattern '\[.*\]\s*' was not found when selecting region to insert in '/root/ncf/tests/acceptance/workdir/__30_generic_methods_file_ensure_lines_present_in_ini_section_cf/tmp/test2.ini'

(only on 3.9)

Maybe linked to:

EOF is  matched as an end of the region in edit_line
      promises only if 'select_end_match_eof' parameter is true.
      (Jira CFE-2263)

from 3.9 changelog.

That's it! We cannot use select_end_match_eof though as it is not available in 3.7, we have to fix the test.

https://tracker.mender.io/browse/CFE-2263