feat(describe): improves logic around hooks

src/Support/ChainableClosure.php

@@ -12,6 +12,22 @@ use Pest\Exceptions\ShouldNotHappen;
  */
 final class ChainableClosure
 {
+    /**
+     * Calls the given `$closure` when the given condition is true.
+     */
+    public static function when(Closure $condition, Closure $next): Closure
+    {
+        return function () use ($condition, $next): void {
+            if (! is_object($this)) { // @phpstan-ignore-line
+                throw ShouldNotHappen::fromMessage('$this not bound to chainable closure.');
+            }
+
+            if (\Pest\Support\Closure::bind($condition, $this, self::class)(...func_get_args())) {
+                \Pest\Support\Closure::bind($next, $this, self::class)(...func_get_args());
+            }
+        };
+    }
+
     /**
      * Calls the given `$closure` and chains the `$next` closure.
      */