Add test for the simultaneous presence of --force-check and --skip-update-check.

Signed-off-by: Saul Baizman <[email protected]>

Author: baizmandesign

src/WP_CLI/CommandWithUpgrade.php

@@ -532,6 +532,11 @@ static function ( $result ) {
 	// phpcs:ignore PSR2.Methods.MethodDeclaration.Underscore -- Whitelisting to provide backward compatibility to classes possibly extending this class.
 	protected function _list( $_, $assoc_args ) {
 
+		// If `--force-check` and `--skip-update-check` flags are both present, abort.
+		if ( true === (bool) Utils\get_flag_value( $assoc_args, 'force-check', false ) and true === (bool) Utils\get_flag_value( $assoc_args, 'skip-update-check', false ) ) {
+			WP_CLI::error("{$this->item_type} updates cannot be both force-checked and skipped. Choose one.");
+		}
+
 		// If `--force-check` flag is present, delete the upgrade transient.
 		if ( true === (bool) Utils\get_flag_value( $assoc_args, 'force-check', false ) ) {
 			delete_site_transient( $this->upgrade_transient );