Update HTTP header name in wp-404-caching plugin

The HTTP header name 'X-WP_404_Caching-404-Cache' has been updated to 'X-WP-404-Cache' in class-full-page-cache-404 and all its instances within the project. Similarly, the unit tests have been updated to reflect these changes ensuring consistency in the caching system.

src/features/class-full-page-cache-404.php

@@ -164,7 +164,7 @@ public static function get_cached_response_with_headers(): string {
 	}
 
 	/**
-	 * Send X-WP_404_Caching HTTP Header.
+	 * Send X-WP-404-Cache HTTP Header.
 	 *
 	 * @param string $type HIT or MISS.
 	 * @param bool   $stale Whether the stale cache is in use. Default false.
@@ -176,11 +176,11 @@ public static function send_header( string $type, bool $stale = false ): void {
 		}
 
 		if ( ! $stale && 'HIT' === $type ) {
-			header( 'X-WP_404_Caching-404-Cache: HIT' );
+			header( 'X-WP-404-Cache: HIT' );
 		} elseif ( $stale && 'HIT' === $type ) {
-			header( 'X-WP_404_Caching-404-Cache: HIT (stale)' );
+			header( 'X-WP-404-Cache: HIT (stale)' );
 		} elseif ( 'MISS' === $type ) {
-			header( 'X-WP_404_Caching-404-Cache: MISS' );
+			header( 'X-WP-404-Cache: MISS' );
 		}
 	}
 

tests/Feature/FullPageCache404Test.php

@@ -22,7 +22,7 @@
  *
  * @link https://mantle.alley.com/testing/test-framework.html
  */
-class Test_Full_Page_Cache_404 extends TestCase {
+final class FullPageCache404Test extends TestCase {
 	use Refresh_Database;
 	use Admin_Screen;
 
@@ -215,7 +215,7 @@ public function test_full_page_cache_not_returned_for_non_404(): void {
 		$post_id  = self::factory()->post->create( [ 'post_title' => 'Hello World' ] );
 		$response = $this->get( get_the_permalink( $post_id ) );
 		$response->assertStatus( 200 );
-		$response->assertHeaderMissing( 'X-Alleyvate-404-Cache' );
+		$response->assertHeaderMissing( 'X-WP-404-Cache' );
 		$response->assertSee( 'Hello World' );
 
 		$this->assertFalse(