TDD the Chess\Eval\CombinedAttackEval class

[programarivm]

A new evaluation feature called Chess\Eval\CombinedAttackEval needs to be implemented in the php-chess/src/Eval folder. The PHPUnit tests are to be written in the php-chess/tests/unit/Eval/CombinedAttackEvalTest.php file accordingly. This is for when multiple pieces are targeting one of the opponent's pieces simultaneously.

[programarivm]

Rather than implementing a new evaluation feature, it looks like it is the threat evaluation what needs to be fixed. The threat evaluation is working correctly in many positions when a piece is at risk of being lost. The signal though is not triggered in the position below. The king alone seems not to be taken into consideration as a defending piece.