While this change is not 100% required now, it's good habit
and we are checking for it since Moodle 4.4.
All the changes in this commit have been applied automatically
using the moodle.PHPUnit.TestReturnType sniff and are, exclusively
adding the ": void" return types when missing.
Tests cover
- get_overall_completion_state()
- is_available()
- validate_rule()
Tests don't cover
- methods that rely on static methods such as:
- is_defined()
- static methods in the class because they can't be mocked
- abstract methods that can be tested better by the plugins
that extend activity_custom_completion such as:
- get_state()
- get_defined_custom_rules()
- get_custom_rule_descriptions()
Andrew Nicols