test: add pairing guide widget tests

test/features/mobile/mobile_pairing_guide_suite.dart

@@ -0,0 +1,97 @@
+@TestOn('vm')
+library;
+
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:xworkmate/features/mobile/mobile_gateway_pairing_guide_page.dart';
+import 'package:xworkmate/theme/app_theme.dart';
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+
+  const mobileScannerChannel = MethodChannel(
+    'dev.steenbakker.mobile_scanner/scanner/method',
+  );
+
+  setUp(() {
+    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
+        .setMockMethodCallHandler(mobileScannerChannel, (call) async => null);
+  });
+
+  tearDown(() {
+    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
+        .setMockMethodCallHandler(mobileScannerChannel, null);
+  });
+
+  Future<void> pumpGuide(
+    WidgetTester tester, {
+    required bool supportsQrScan,
+    required VoidCallback onManual,
+    required Future<void> Function(String setupCode) onScanned,
+  }) async {
+    tester.view.devicePixelRatio = 1;
+    tester.view.physicalSize = const Size(430, 1200);
+    addTearDown(() {
+      tester.view.resetPhysicalSize();
+      tester.view.resetDevicePixelRatio();
+    });
+
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: AppTheme.light(platform: TargetPlatform.iOS),
+        darkTheme: AppTheme.dark(platform: TargetPlatform.iOS),
+        home: MobileGatewayPairingGuidePage(
+          supportsQrScan: supportsQrScan,
+          onManualInput: onManual,
+          onScannedSetupCode: onScanned,
+        ),
+      ),
+    );
+    await tester.pump();
+  }
+
+  testWidgets('guide shows xworkmate commands', (tester) async {
+    await pumpGuide(
+      tester,
+      supportsQrScan: true,
+      onManual: () {},
+      onScanned: (_) async {},
+    );
+
+    expect(find.text('配对网关'), findsOneWidget);
+    expect(find.text('npm install -g xworkmate'), findsOneWidget);
+    expect(find.text('xworkmate pair'), findsOneWidget);
+    expect(
+      find.byKey(const ValueKey('pairing-guide-install-command')),
+      findsOneWidget,
+    );
+  });
+
+  testWidgets('manual button triggers callback', (tester) async {
+    var manualTapped = false;
+    await pumpGuide(
+      tester,
+      supportsQrScan: true,
+      onManual: () => manualTapped = true,
+      onScanned: (_) async {},
+    );
+
+    await tester.tap(find.byKey(const ValueKey('pairing-guide-manual-button')));
+    await tester.pumpAndSettle();
+    expect(manualTapped, isTrue);
+  });
+
+  testWidgets('android scan button shows placeholder toast', (tester) async {
+    await pumpGuide(
+      tester,
+      supportsQrScan: false,
+      onManual: () {},
+      onScanned: (_) async {},
+    );
+
+    await tester.tap(find.byKey(const ValueKey('pairing-guide-scan-button')));
+    await tester.pump();
+    expect(find.textContaining('Android 扫码即将支持'), findsOneWidget);
+  });
+}