Add cache-clearning functionality

Author: oliverklee

src/Property/Selector/SpecificityCalculator.php

@@ -8,8 +8,6 @@
  * Utility class to calculate the specificity of a CSS selector.
  *
  * The results are cached to avoid recalculating the specificity of the same selector multiple times.
- *
- * @internal
  */
 final class SpecificityCalculator
 {
@@ -56,7 +54,11 @@ final class SpecificityCalculator
     private static $cache = [];
 
     /**
+     * Calculates the specificity of the given CSS selector.
+     *
      * @return int<0, max>
+     *
+     * @internal
      */
     public static function calculate(string $selector): int
     {
@@ -72,4 +74,12 @@ public static function calculate(string $selector): int
 
         return self::$cache[$selector];
     }
+
+    /**
+     * Clears the cache in order to lower memory usage.
+     */
+    public static function clearCache(): void
+    {
+        self::$cache = [];
+    }
 }

tests/Unit/Property/Selector/SpecificityCalculatorTest.php

@@ -12,6 +12,11 @@
  */
 final class SpecificityCalculatorTest extends TestCase
 {
+    protected function tearDown(): void
+    {
+        SpecificityCalculator::clearCache();
+    }
+
     /**
      * @return array<string, array{0: non-empty-string, 1: int<0, max>}>
      */
@@ -42,4 +47,48 @@ public function calculateReturnsSpecificityForProvidedSelector(
     ): void {
         self::assertSame($expectedSpecificity, SpecificityCalculator::calculate($selector));
     }
+
+    /**
+     * @test
+     *
+     * @param non-empty-string $selector
+     * @param int<0, max> $expectedSpecificity
+     *
+     * @dataProvider provideSelectorsAndSpecificities
+     */
+    public function calculateAfterClearingCacheReturnsSpecificityForProvidedSelector(
+        string $selector,
+        int $expectedSpecificity
+    ): void {
+        SpecificityCalculator::clearCache();
+
+        self::assertSame($expectedSpecificity, SpecificityCalculator::calculate($selector));
+    }
+
+    /**
+     * @test
+     */
+    public function calculateCalledTwoTimesReturnsSameSpecificityForProvidedSelector(): void
+    {
+        $selector = '#test .help';
+
+        $firstResult = SpecificityCalculator::calculate($selector);
+        $secondResult = SpecificityCalculator::calculate($selector);
+
+        self::assertSame($firstResult, $secondResult);
+    }
+
+    /**
+     * @test
+     */
+    public function calculateCalledReturnsSameSpecificityForProvidedSelectorBeforeAndAfterClearingCache(): void
+    {
+        $selector = '#test .help';
+
+        $firstResult = SpecificityCalculator::calculate($selector);
+        SpecificityCalculator::clearCache();
+        $secondResult = SpecificityCalculator::calculate($selector);
+
+        self::assertSame($firstResult, $secondResult);
+    }
 }