Render Checkout/Cart containing pages without template overriding

src/Templates/CartTemplate.php

@@ -32,7 +32,8 @@ public static function get_placeholder_page() {
 	 * @return boolean
 	 */
 	protected function is_active_template() {
-		return is_cart();
+		global $post;
+		return get_option( 'woocommerce_cart_page_endpoint' ) === $post->post_name;
 	}
 
 	/**

src/Templates/CheckoutTemplate.php

@@ -41,6 +41,7 @@ public static function get_template_title() {
 	 * @return boolean
 	 */
 	public function is_active_template() {
-		return is_checkout();
+		global $post;
+		return get_option( 'woocommerce_checkout_page_endpoint' ) === $post->post_name;
 	}
 }