Add Behat tests for wpdb fallback in drop, reset, and import commands

Agent-Logs-Url: https://github.com/wp-cli/db-command/sessions/fa41acc5-de2a-4dc3-9f7a-f5b282ed670a

Co-authored-by: swissspidy <841956+swissspidy@users.noreply.github.com>

Author: Copilot

features/db-import.feature

@@ -69,6 +69,34 @@ Feature: Import a WordPress database
       Success: Imported from 'wp_cli_test.sql'.
       """
 
+  @require-mysql-or-mariadb
+  Scenario: Database import falls back to wpdb when mysql binary is unavailable
+    Given a WP install
+    And a fake-bin/mysql file:
+      """
+      #!/bin/sh
+      exit 127
+      """
+    And a fake-bin/mariadb file:
+      """
+      #!/bin/sh
+      exit 127
+      """
+
+    When I run `wp db export wp_cli_test.sql`
+    Then the wp_cli_test.sql file should exist
+
+    When I run `chmod +x fake-bin/mysql fake-bin/mariadb`
+    And I run `env PATH={RUN_DIR}/fake-bin:$PATH wp db import wp_cli_test.sql --debug`
+    Then STDOUT should be:
+      """
+      Success: Imported from 'wp_cli_test.sql'.
+      """
+    And STDERR should contain:
+      """
+      MySQL/MariaDB binary not available, falling back to wpdb for import.
+      """
+
   # SQLite doesn't support the --dbuser flag.
   @require-mysql-or-mariadb
   Scenario: Import from database name path by default with passed-in dbuser/dbpass

features/db.feature

@@ -383,6 +383,56 @@ Feature: Perform database operations
       Query succeeded. Rows affected: 1
       """
 
+  @require-mysql-or-mariadb
+  Scenario: Database drop falls back to wpdb when mysql binary is unavailable
+    Given a WP install
+    And a fake-bin/mysql file:
+      """
+      #!/bin/sh
+      exit 127
+      """
+    And a fake-bin/mariadb file:
+      """
+      #!/bin/sh
+      exit 127
+      """
+
+    When I run `chmod +x fake-bin/mysql fake-bin/mariadb`
+    And I run `env PATH={RUN_DIR}/fake-bin:$PATH wp db drop --yes --debug`
+    Then STDOUT should contain:
+      """
+      Success: Database dropped.
+      """
+    And STDERR should contain:
+      """
+      Query via wpdb:
+      """
+
+  @require-mysql-or-mariadb
+  Scenario: Database reset falls back to wpdb when mysql binary is unavailable
+    Given a WP install
+    And a fake-bin/mysql file:
+      """
+      #!/bin/sh
+      exit 127
+      """
+    And a fake-bin/mariadb file:
+      """
+      #!/bin/sh
+      exit 127
+      """
+
+    When I run `chmod +x fake-bin/mysql fake-bin/mariadb`
+    And I run `env PATH={RUN_DIR}/fake-bin:$PATH wp db reset --yes --debug`
+    Then STDOUT should contain:
+      """
+      Success: Database reset.
+      """
+    And STDERR should contain:
+      """
+      Query via wpdb:
+      """
+
   @require-sqlite
   Scenario: SQLite DB CRUD operations
     Given a WP install

src/DB_Command.php

@@ -1947,6 +1947,11 @@ protected function run_query( $query, $assoc_args = [] ) {
 			WP_CLI::debug( "Query via wpdb: {$query}", 'db' );
 			$this->maybe_load_wpdb();
 			global $wpdb;
+
+			if ( ! isset( $wpdb ) ) {
+				WP_CLI::error( 'WordPress database (wpdb) is not available. Please install MySQL or MariaDB client tools.' );
+			}
+
 			// phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
 			$result = $wpdb->query( $query );
 			if ( false === $result ) {