ExperimentTest.php

<?php

use Scientist\Experiment;
use Scientist\Laboratory;
use Scientist\Matchers\StandardMatcher;

class ExperimentTest extends \PHPUnit\Framework\TestCase
{
    public function test_that_a_new_experiment_can_be_created()
    {
        $e = new Experiment('test experiment', new Laboratory);
        $this->assertInstanceOf(Experiment::class, $e);
    }

    public function test_that_experiment_name_is_set()
    {
        $e = new Experiment('test experiment', new Laboratory);
        $this->assertEquals('test experiment', $e->getName());
    }

    public function test_that_a_control_callback_can_be_defined()
    {
        $e = new Experiment('test experiment', new Laboratory);
        $control = function () {
            return true;
        };
        $e->control($control);
        $this->assertSame($control, $e->getControl());
    }

    public function test_that_control_context_defaults_to_null()
    {
        $e = new Experiment('test experiment', new Laboratory);
        $e->control(function () {
            return true;
        });
        $this->assertNull($e->getControlContext());
    }

    public function test_that_control_context_can_be_defined()
    {
        $context = ['foo' => 'bar'];
        $e = new Experiment('test experiment', new Laboratory);
        $e->control(function () {
            return true;
        }, $context);
        $this->assertSame($context, $e->getControlContext());
    }

    public function test_that_a_trial_callback_can_be_defined()
    {
        $e = new Experiment('test experiment', new Laboratory);
        $trial = function () {
            return true;
        };
        $e->trial('trial', $trial);
        $this->assertSame($trial, $e->getTrial('trial'));
    }

    public function test_that_multiple_trial_callbacks_can_be_defined()
    {
        $e = new Experiment('test experiment', new Laboratory);
        $first = function () {
            return 'first';
        };
        $second = function () {
            return 'second';
        };
        $third = function () {
            return 'third';
        };
        $e->trial('first', $first);
        $e->trial('second', $second);
        $e->trial('third', $third);
        $expected = [
            'first',
            'second',
            'third',
        ];
        $trials = $e->getTrials();
        $this->assertSame($expected, \array_keys($trials));
        $this->assertContainsOnlyInstancesOf(\Scientist\Trial::class, $trials);
    }

    public function test_that_a_chance_variable_can_be_set()
    {
        $chance = $this->createMock('\Scientist\Chances\Chance');
        $e = new Experiment('test experiment', new Laboratory);
        $e->chance($chance);
        $this->assertEquals($chance, $e->getChance());
    }

    public function test_that_an_experiment_matcher_can_be_set()
    {
        $e = new Experiment('test experiment', new Laboratory);
        $e->matcher(new StandardMatcher);
        $this->assertInstanceOf(StandardMatcher::class, $e->getMatcher());
    }

    public function test_that_an_experiment_laboratory_can_be_set()
    {
        $l = new Laboratory;
        $e = new Experiment('test experiment', $l);
        $this->assertInstanceOf(Laboratory::class, $e->getLaboratory());
        $this->assertSame($l, $e->getLaboratory());
    }

    public function test_that_running_experiment_with_no_laboratory_executes_control()
    {
        $e = new Experiment('test experiment', new Laboratory);
        $e->control(function () { return 'foo'; });
        $v = $e->run();
        $this->assertEquals('foo', $v);
    }

    public function test_that_running_experiment_with_zero_chance_executes_control()
    {
        $chance = $this->getMockChance();
        $chance->expects($this->once())
            ->method('shouldRun')
            ->willReturn(false);

        $l = new Laboratory;
        $v = $l->experiment('test experiment')
            ->control(function () { return 'foo'; })
            ->chance($chance)
            ->run();

        $this->assertEquals('foo', $v);
    }

    public function getMockChance()
    {
        return $this->getMockBuilder('\Scientist\Chances\Chance')
            ->disableOriginalConstructor()
            ->disableProxyingToOriginalMethods()
            ->getMock();
    }
}