[url_launcher] Migrate unit tests to NNBD

Replaces the problematic Mockito mock with a manual mock that handles
null and non-null types correctly.

Author: stuartmorgan-g

packages/url_launcher/url_launcher/example/test/url_launcher_example_test.dart

@@ -2,9 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// TODO(egarciad): Remove once mockito is migrated to null safety.
-// @dart = 2.9
-
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/material.dart';
 import 'package:mockito/mockito.dart';

packages/url_launcher/url_launcher/pubspec.yaml

@@ -39,7 +39,7 @@ dev_dependencies:
   flutter_test:
     sdk: flutter
   test: ^1.16.3
-  mockito: ^5.0.0-nullsafety.7
+  mockito: ^5.0.0
   plugin_platform_interface: ^2.0.0
   pedantic: ^1.10.0
 

packages/url_launcher/url_launcher/test/link_test.dart

@@ -2,9 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// TODO(egarciad): Remove once Mockito has been migrated to null safety.
-// @dart = 2.9
-
 import 'dart:ui';
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
@@ -20,7 +17,7 @@ void main() {
   final MockUrlLauncher mock = MockUrlLauncher();
   UrlLauncherPlatform.instance = mock;
 
-  PlatformMessageCallback realOnPlatformMessage;
+  PlatformMessageCallback? realOnPlatformMessage;
   setUp(() {
     realOnPlatformMessage = window.onPlatformMessage;
   });
@@ -31,11 +28,11 @@ void main() {
   group('$Link', () {
     testWidgets('handles null uri correctly', (WidgetTester tester) async {
       bool isBuilt = false;
-      FollowLink followLink;
+      FollowLink? followLink;
 
       final Link link = Link(
         uri: null,
-        builder: (BuildContext context, FollowLink followLink2) {
+        builder: (BuildContext context, FollowLink? followLink2) {
           isBuilt = true;
           followLink = followLink2;
           return Container();
@@ -50,12 +47,12 @@ void main() {
 
     testWidgets('calls url_launcher for external URLs with blank target',
         (WidgetTester tester) async {
-      FollowLink followLink;
+      FollowLink? followLink;
 
       await tester.pumpWidget(Link(
         uri: Uri.parse('http://example.com/foobar'),
         target: LinkTarget.blank,
-        builder: (BuildContext context, FollowLink followLink2) {
+        builder: (BuildContext context, FollowLink? followLink2) {
           followLink = followLink2;
           return Container();
         },
@@ -64,7 +61,7 @@ void main() {
       when(mock.canLaunch('http://example.com/foobar'))
           .thenAnswer((realInvocation) => Future<bool>.value(true));
       clearInteractions(mock);
-      await followLink();
+      await followLink!();
 
       verifyInOrder([
         mock.canLaunch('http://example.com/foobar'),
@@ -82,12 +79,12 @@ void main() {
 
     testWidgets('calls url_launcher for external URLs with self target',
         (WidgetTester tester) async {
-      FollowLink followLink;
+      FollowLink? followLink;
 
       await tester.pumpWidget(Link(
         uri: Uri.parse('http://example.com/foobar'),
         target: LinkTarget.self,
-        builder: (BuildContext context, FollowLink followLink2) {
+        builder: (BuildContext context, FollowLink? followLink2) {
           followLink = followLink2;
           return Container();
         },
@@ -96,7 +93,7 @@ void main() {
       when(mock.canLaunch('http://example.com/foobar'))
           .thenAnswer((realInvocation) => Future<bool>.value(true));
       clearInteractions(mock);
-      await followLink();
+      await followLink!();
 
       verifyInOrder([
         mock.canLaunch('http://example.com/foobar'),
@@ -125,21 +122,21 @@ void main() {
       final List<MethodCall> frameworkCalls = <MethodCall>[];
       window.onPlatformMessage = (
         String name,
-        ByteData data,
-        PlatformMessageResponseCallback callback,
+        ByteData? data,
+        PlatformMessageResponseCallback? callback,
       ) {
         frameworkCalls.add(_codec.decodeMethodCall(data));
-        realOnPlatformMessage(name, data, callback);
+        realOnPlatformMessage!(name, data, callback);
       };
 
       final Uri uri = Uri.parse('/foo/bar');
-      FollowLink followLink;
+      FollowLink? followLink;
 
       await tester.pumpWidget(MaterialApp(
         routes: <String, WidgetBuilder>{
           '/': (BuildContext context) => Link(
                 uri: uri,
-                builder: (BuildContext context, FollowLink followLink2) {
+                builder: (BuildContext context, FollowLink? followLink2) {
                   followLink = followLink2;
                   return Container();
                 },
@@ -151,7 +148,7 @@ void main() {
       engineCalls.clear();
       frameworkCalls.clear();
       clearInteractions(mock);
-      await followLink();
+      await followLink!();
 
       // Shouldn't use url_launcher when uri is an internal route name.
       verifyZeroInteractions(mock);
@@ -191,19 +188,19 @@ void main() {
       final List<MethodCall> frameworkCalls = <MethodCall>[];
       window.onPlatformMessage = (
         String name,
-        ByteData data,
-        PlatformMessageResponseCallback callback,
+        ByteData? data,
+        PlatformMessageResponseCallback? callback,
       ) {
         frameworkCalls.add(_codec.decodeMethodCall(data));
-        realOnPlatformMessage(name, data, callback);
+        realOnPlatformMessage!(name, data, callback);
       };
 
       final Uri uri = Uri.parse('/foo/bar');
-      FollowLink followLink;
+      FollowLink? followLink;
 
       final Link link = Link(
         uri: uri,
-        builder: (BuildContext context, FollowLink followLink2) {
+        builder: (BuildContext context, FollowLink? followLink2) {
           followLink = followLink2;
           return Container();
         },
@@ -218,7 +215,7 @@ void main() {
       engineCalls.clear();
       frameworkCalls.clear();
       clearInteractions(mock);
-      await followLink();
+      await followLink!();
 
       // Shouldn't use url_launcher when uri is an internal route name.
       verifyZeroInteractions(mock);
@@ -261,8 +258,8 @@ class MockRouteInformationParser extends Mock
   }
 }
 
-class MockRouterDelegate extends Mock implements RouterDelegate {
-  MockRouterDelegate({@required this.builder});
+class MockRouterDelegate extends Mock implements RouterDelegate<Object> {
+  MockRouterDelegate({required this.builder});
 
   final WidgetBuilder builder;