start fixing integration tests

inc/Engine/Common/Head/Subscriber.php

@@ -35,7 +35,8 @@ class Subscriber implements Subscriber_Interface {
 	 */
 	public static function get_subscribed_events() {
 		return [
-			'rocket_head' => 'print_head_elements',
+			'rocket_buffer' => [ 'insert_rocket_head', 100000 ],
+			'rocket_head'   => 'print_head_elements',
 		];
 	}
 
@@ -136,4 +137,29 @@ private function prepare_element( $element ) {
 
 		return $open_tag . ' ' . $attributes_html . '>' . $inner_content . $close_tag;
 	}
+
+	/**
+	 * Insert rocket_head into the buffer HTML
+	 *
+	 * @param string $html Buffer HTML.
+	 * @return string
+	 */
+	public function insert_rocket_head( $html ) {
+		if ( empty( $html ) ) {
+			return $html;
+		}
+
+		$filtered_buffer = preg_replace(
+			'#</title>#iU',
+			'</title>' . wpm_apply_filters_typed( 'string', 'rocket_head', '' ),
+			$html,
+			1
+		);
+
+		if ( empty( $filtered_buffer ) ) {
+			return $html;
+		}
+
+		return $filtered_buffer;
+	}
 }

inc/Engine/CriticalPath/CriticalCSSSubscriber.php

@@ -639,7 +639,7 @@ public function insert_css_in_head( $items ) {
 	 * @return string
 	 */
 	public function get_critical_css_content() {
-		return $this->critical_css_content;
+		return $this->should_async_css() ? $this->critical_css_content : '';
 	}
 
 	/**

inc/Engine/Optimization/Buffer/Subscriber.php

@@ -33,7 +33,6 @@ public function __construct( Optimization $optimizer ) {
 	public static function get_subscribed_events() {
 		return [
 			'template_redirect' => [ 'start_content_process', 2 ],
-			'rocket_buffer' => [ 'insert_rocket_head', 100000 ],
 		];
 	}
 
@@ -45,29 +44,4 @@ public static function get_subscribed_events() {
 	public function start_content_process() {
 		return $this->optimizer->maybe_init_process();
 	}
-
-	/**
-	 * Insert rocket_head into the buffer HTML
-	 *
-	 * @param string $html Buffer HTML.
-	 * @return string
-	 */
-	public function insert_rocket_head( $html ) {
-		if ( empty( $html ) ) {
-			return $html;
-		}
-
-		$filtered_buffer = preg_replace(
-			'#</title>#iU',
-			'</title>' . wpm_apply_filters_typed( 'string', 'rocket_head', '' ),
-			$html,
-			1
-		);
-
-		if ( empty( $filtered_buffer ) ) {
-			return $html;
-		}
-
-		return $filtered_buffer;
-	}
 }

inc/Engine/Optimization/GoogleFonts/Combine.php

@@ -64,7 +64,7 @@ public function optimize( $html ): string {
 			function ( $font ) use ( $exclusions ) {
 				return ! $this->is_excluded( $font[0], $exclusions );
 			}
-			);
+		);
 
 		$num_fonts = count( $filtered_fonts );
 

tests/Integration/IsolateHookTrait.php

@@ -11,6 +11,49 @@
 
 	protected $original_wp_priorities;
 
+	protected function unregisterAllCallbacksExceptMulti( $event_name, $methods = [] ) {
+		global $wp_filter;
+		$this->original_wp_filter = $wp_filter[ $event_name ]->callbacks;
+
+		foreach ( $methods as $priority => $method_name ) {
+			foreach ( $this->original_wp_filter[ $priority ] as $key => $config ) {
+
+				// Skip if not this tests callback.
+				if ( substr( $key, - strlen( $method_name ) ) !== $method_name ) {
+					continue;
+				}
+
+				$wp_filter[ $event_name ]->callbacks = [
+					$priority => [ $key => $config ],
+				];
+			}
+		}
+
+		try {
+			$wp_hooks = $wp_filter[ $event_name ];
+			$reflection = new ReflectionClass($wp_hooks);
+			$priorities_property = $reflection->getProperty('priorities');
+			$priorities_property->setAccessible(true);
+			$this->original_wp_priorities = $priorities_property->getValue($wp_hooks);
+			$priorities = $priorities_property->getValue($wp_hooks);
+		} catch (ReflectionException $e) {
+			return;
+		}
+
+		foreach ($this->original_wp_priorities as $priority) {
+			if ( key_exists($priority, $wp_filter[ $event_name ]->callbacks)) {
+				continue;
+			}
+
+			$priorities = array_values(array_filter($priorities, function ($current) use ($priority) {
+				return $current !== $priority;
+			}));
+
+		}
+
+		$priorities_property->setValue($wp_hooks, $priorities);
+	}
+
 	protected function unregisterAllCallbacksExcept( $event_name, $method_name, $priority = 10 ) {
 		global $wp_filter;
 		$this->original_wp_filter = $wp_filter[ $event_name ]->callbacks;

tests/Integration/inc/Engine/Optimization/GoogleFonts/Combine/optimize.php

@@ -29,7 +29,7 @@ public function set_up() {
 			],
         ];
 
-        $this->unregisterAllCallbacksExcept('rocket_buffer', 'process', 17 );
+        $this->unregisterAllCallbacksExceptMulti('rocket_buffer', [ 17 => 'process', 100000 => 'insert_rocket_head' ] );
 		add_filter('rocket_exclude_locally_host_fonts', [ $this, 'exclude_locally_host_fonts' ] ); // @phpstan-ignore-line
 	}
 
@@ -84,7 +84,7 @@ private function doTest( $config, $original, $expected ) {
 		$actual = apply_filters( 'rocket_buffer', $original );
 
 		$this->assertSame(
-			$this->format_the_html( $expected ),
+			$this->format_the_html( $expected['html'] ),
 			$this->format_the_html( $actual )
 		);
 	}