Add support for withAnyArgs method for onFilter calls.

[badasswp]

Summary

This PR implements a new method called withAnyArgs for onFilter calls. This method is particularly useful in test cases where we do not care about the filter arguments passed in but just its return value like so:

WP_Mock::onFilter('custom_content_filter')
    ->withAnyArgs()
    ->reply('This is filtered')

Closes: #156

Details

I have introduced a static array called $filtersWithAnyArgs that basically acts as an associative array for filter names mapped to random integer values.

This array will help us store random integers at the point where the withAnyArgs method is called, so that we can check for those later in the apply method and accurately set our passed in args.

Run tests:

vendor/bin/phpunit ./tests/Unit/WP_MockTest.php 

Contributor checklist

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly
• I have added tests to cover changes introduced by this pull request
• All new and existing tests pass

Testing

Create class like so:

namespace MyPlugin;

class MyClass
{
    public function filterContent() : string
    {
        return apply_filters('custom_content_filter', 'This is unfiltered');
    }
}

Create Test like so:

use MyPlugin\MyClass;
use WP_Mock;
use WP_Mock\Tools\TestCase as TestCase;

final class MyClassTest extends TestCase
{
    public function testCanFilterContent() : void 
    {
        WP_Mock::onFilter('custom_content_filter')
            ->withAnyArgs()
            ->reply('This is filtered');

        $content = (new MyClass())->filterContent();

        $this->assertEquals('This is filtered', $content);
    }
}

Run test, it should pass successfully using the withAnyArgs method:

composer run test

Reviewer checklist

• Code changes review
• Documentation changes review
• Unit tests pass
• Static analysis passes

[coveralls]

coverage: 66.142% (-0.3%) from 66.446%
when pulling 3b4f99e on badasswp:feat/add-with-anything-method-for-on-filter
into bdbb090 on 10up:trunk.

[agibson-godaddy]

Thanks for putting this together! Just one suggestion.

[agibson-godaddy]

Nice work!! :)