php-ml/tests/Phpml/Classification/DecisionTreeTest.php

<?php

declare(strict_types=1);

namespace tests\Classification;

use Phpml\Classification\DecisionTree;

class DecisionTreeTest extends \PHPUnit_Framework_TestCase
{
    public $data = [
        ['sunny',        85,        85,    'false',    'Dont_play'    ],
        ['sunny',        80,    90,    'true',        'Dont_play'    ],
        ['overcast',    83,    78,    'false',    'Play'        ],
        ['rain',        70,    96,    'false',    'Play'        ],
        ['rain',        68,    80,    'false',    'Play'        ],
        ['rain',        65,    70,    'true',    'Dont_play'    ],
        ['overcast',    64,    65,    'true',    'Play'        ],
        ['sunny',        72,    95,    'false',    'Dont_play'    ],
        ['sunny',        69,    70,    'false',    'Play'        ],
        ['rain',        75,    80,    'false',    'Play'        ],
        ['sunny',        75,    70,    'true',    'Play'        ],
        ['overcast',    72,    90,    'true',    'Play'        ],
        ['overcast',    81,    75,    'false',    'Play'        ],
        ['rain',        71,    80,    'true',    'Dont_play'    ]
    ];

    public function getData()
    {
        static $data = null, $targets = null;
        if ($data == null) {
            $data = $this->data;
            $targets = array_column($data, 4);
            array_walk($data, function (&$v) {
                array_splice($v, 4, 1);
            });
        }
        return [$data, $targets];
    }

    public function testPredictSingleSample()
    {
        list($data, $targets) = $this->getData();
        $classifier = new DecisionTree(5);
        $classifier->train($data, $targets);
        $this->assertEquals('Dont_play', $classifier->predict(['sunny', 78, 72, 'false']));
        $this->assertEquals('Play', $classifier->predict(['overcast', 60, 60, 'false']));
        $this->assertEquals('Dont_play', $classifier->predict(['rain', 60, 60, 'true']));

        return $classifier;
    }

    public function testTreeDepth()
    {
        list($data, $targets) = $this->getData();
        $classifier = new DecisionTree(5);
        $classifier->train($data, $targets);
        $this->assertTrue(5 >= $classifier->actualDepth);
    }
}