Make WooCommerce core play nice with Codeception (#11845)

If is_blog_installed() is false then skip some installation steps that
are performed on the 'init' action and which require the database to be
available

includes/class-wc-cache-helper.php

@@ -167,6 +167,11 @@ class WC_Cache_Helper {
 	 * Prevent caching on dynamic pages.
 	 */
 	public static function prevent_caching() {
+
+		if ( ! is_blog_installed() ) {
+			return;
+		}
+
 		if ( false === ( $wc_page_uris = get_transient( 'woocommerce_cache_excluded_uris' ) ) ) {
 			$wc_page_uris   = array_filter( array_merge( self::get_page_uris( 'cart' ), self::get_page_uris( 'checkout' ), self::get_page_uris( 'myaccount' ) ) );
 	    	set_transient( 'woocommerce_cache_excluded_uris', $wc_page_uris );

includes/class-wc-install.php

@@ -137,6 +137,10 @@ class WC_Install {
 	public static function install() {
 		global $wpdb;
 
+		if ( ! is_blog_installed() ) {
+			return;
+		}
+
 		if ( ! defined( 'WC_INSTALLING' ) ) {
 			define( 'WC_INSTALLING', true );
 		}

includes/class-wc-post-types.php

@@ -36,6 +36,11 @@ class WC_Post_types {
 	 * Register core taxonomies.
 	 */
 	public static function register_taxonomies() {
+
+		if ( ! is_blog_installed() ) {
+			return;
+		}
+
 		if ( taxonomy_exists( 'product_type' ) ) {
 			return;
 		}
@@ -226,6 +231,11 @@ class WC_Post_types {
 	 * Register core post types.
 	 */
 	public static function register_post_types() {
+
+		if ( ! is_blog_installed() ) {
+			return;
+		}
+
 		if ( post_type_exists( 'product' ) ) {
 			return;
 		}

woocommerce.php

@@ -476,6 +476,11 @@ final class WooCommerce {
 	 * @since 2.2
 	 */
 	private function load_webhooks() {
+
+		if ( ! is_blog_installed() ) {
+			return;
+		}
+
 		if ( false === ( $webhooks = get_transient( 'woocommerce_webhook_ids' ) ) ) {
 			$webhooks = get_posts( array(
 				'fields'         => 'ids',