Add different intersection algos comparing test

tests/IntersectionCheckersComparisonTest.php

@@ -0,0 +1,104 @@
+<?php
+
+declare(strict_types=1);
+
+use Danon\IntervalTree\IntervalTree;
+use PHPUnit\Framework\TestCase;
+
+interface IntersectionsChecker
+{
+    /**
+     * Check there are intersections for each Y-interval in X-intervals
+     *
+     * @param array $xList
+     * @param array $yList
+     * @return Iterator
+     */
+    public function checkIntersections(array $xList, array $yList): Iterator;
+}
+
+class BruteForceIntersectionsChecker implements IntersectionsChecker
+{
+    public function checkIntersections(array $xList, array $yList): Iterator
+    {
+        $checkIntersection = function (array $x, array $y) {
+            return max($x[0], $y[0]) <= min($x[1], $y[1]);
+        };
+
+        foreach ($yList as $yInterval) {
+            $hasIntersection = false;
+            foreach ($xList as $xInterval) {
+                if ($checkIntersection($xInterval, $yInterval)) {
+                    $hasIntersection = true;
+                    break;
+                }
+            }
+            yield $hasIntersection;
+        }
+    }
+}
+
+class IntervalTreeIntersectionsChecker implements IntersectionsChecker
+{
+    public function checkIntersections(array $xList, array $yList): Iterator
+    {
+        $tree = new IntervalTree();
+        foreach ($xList as $xInterval) {
+            $tree->insert($xInterval);
+        }
+
+        foreach ($yList as $yInterval) {
+            yield $tree->hasIntersection($yInterval);
+        }
+    }
+}
+
+final class IntersectionCheckersComparisonTest extends TestCase
+{
+    const INTERVAL_INDEX_MULTIPLIER = 512;
+    const INTERVAL_HIGH_MAX_INCREMENT = 512 / 2 * 3;
+    const NUMBER_OF_INTERVALS = 250;
+
+    protected $x = [];
+    protected $y = [];
+    protected $intersectionCheckers = [];
+
+    function setUp(): void
+    {
+        $genRandomInterval = function (int $rangeIndex) {
+
+            $low = rand(
+                $rangeIndex * self::INTERVAL_INDEX_MULTIPLIER,
+                ($rangeIndex + 1) * self::INTERVAL_INDEX_MULTIPLIER
+            );
+            $high = $low + rand(0, self::INTERVAL_HIGH_MAX_INCREMENT);
+
+            return [$low, $high];
+        };
+
+        // Generate random intervals
+        $this->x = array_map($genRandomInterval, range(0, self::NUMBER_OF_INTERVALS - 1));
+        $this->y = array_map($genRandomInterval, range(0, self::NUMBER_OF_INTERVALS - 1));
+
+        // Instantiate intersection checkers
+        $this->intersectionCheckers = [
+            new BruteForceIntersectionsChecker,
+            new IntervalTreeIntersectionsChecker
+        ];
+    }
+
+
+    function testDifferentIntersectionsCheckers()
+    {
+        // Get check lists for each intersection checker 
+        $checkLists = array_map(function (IntersectionsChecker $checker) {
+            $checksIterator = $checker->checkIntersections($this->x, $this->y);
+            // Convert Y-intersections exists checks into bit-string, like: "01100"
+            return implode('', array_map('intval', iterator_to_array($checksIterator)));
+        }, $this->intersectionCheckers);
+
+        // They are the same?
+        $this->assertGreaterThan(1, count($checkLists));
+        $this->assertEquals(1, count(array_unique($checkLists)));
+    }
+}