* When restoring backup we clean the contentformat and defaultformat
to avoid issue with invalid value.
* Add tests for format and defaultformat so to check that we
filter out invalid formats
* Remove private $basepath variable as it was used one and not always
initialised correctly.
Also:
- change 2 variable/property names, both internal.
- format empty function.
Towards getting it fully phpcs compliant. Note this does not
fix the missing (in all methods) phpdoc blocks.
There are various places where it's not guaranteed that the
variable being used is array, and instead, can be null, bool, int...
We need to check that because php74 warns about it.
Where possible we have used the coalesce operator as
replacement for isset() ternary operations.
Laurent David