feat(structure): add region/city structure model with validation

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

viator-collector/tests/run.php

@@ -0,0 +1,44 @@
+<?php
+/**
+ * Minimal test runner for the WordPress-free parts of the plugin.
+ *
+ *   php tests/run.php
+ */
+
+define( 'ABSPATH', __DIR__ . '/' );
+
+require_once dirname( __DIR__ ) . '/includes/class-vc-structure.php';
+
+function vc_assert_same( $expected, $actual, $msg = '' ) {
+	if ( $expected !== $actual ) {
+		throw new Exception( $msg . "\n  expected: " . var_export( $expected, true ) . "\n  actual:   " . var_export( $actual, true ) );
+	}
+}
+
+function vc_assert_contains( $needle, array $errors ) {
+	if ( ! in_array( $needle, $errors, true ) ) {
+		throw new Exception( 'Missing error: ' . $needle . "\n  got: " . var_export( $errors, true ) );
+	}
+}
+
+foreach ( glob( __DIR__ . '/test-*.php' ) as $file ) {
+	require_once $file;
+}
+
+$passed = 0;
+$failed = 0;
+foreach ( get_defined_functions()['user'] as $fn ) {
+	if ( 0 !== strpos( $fn, 'test_' ) ) {
+		continue;
+	}
+	try {
+		$fn();
+		$passed++;
+	} catch ( Throwable $e ) {
+		$failed++;
+		echo 'FAIL ' . $fn . ': ' . $e->getMessage() . "\n";
+	}
+}
+
+echo $passed . ' passed, ' . $failed . " failed\n";
+exit( $failed ? 1 : 0 );