Added testing utilities used for recording and replaying Reddit API interactions

.travis.yml

@@ -12,6 +12,4 @@ dart:
 dart_task:
   - test: -p vm
   - dartfmt
-
-script:
-  - dartanalyzer --strong --fatal-warnings --fatal-lints .
+  - dartanalyzer --strong --fatal-warnings --fatal-lints

lib/src/reddit.dart

@@ -108,6 +108,13 @@ class Reddit {
     }
   }
 
+  Reddit.fromAuthenticator(Authenticator auth) {
+    if (auth == null) {
+      throw new DRAWAuthenticationError('auth cannot be null.');
+    }
+    _initializationCallback(auth);
+  }
+
   void _initializationCallback(Authenticator auth) {
     _auth = auth;
     _initializedCompleter.complete(true);

pubspec.yaml

@@ -7,6 +7,7 @@ authors:
 dependencies:
   http: 'any'
   oauth2: '>= 1.1.0'
+  test: '^0.12.5'
 
 dev_dependencies:
-  test: '^0.12.5' 
+  reply: '^0.1.2-dev'

test/api_v1_me_test.dart

@@ -0,0 +1,28 @@
+// Copyright (c) 2017, the Dart Reddit API Wrapper  project authors.
+// Please see the AUTHORS file for details. All rights reserved.
+// Use of this source code is governed by a BSD-style license that
+// can be found in the LICENSE file.
+
+import 'dart:async';
+
+import 'package:test/test.dart';
+import 'package:draw/draw.dart';
+import 'package:draw/src/auth.dart';
+
+import 'test_authenticator.dart';
+
+Future main() async {
+  test('api/v1/me_RawTest', () async {
+    final testAuth = new TestAuthenticator('test/records/api_v1_me_raw.json');
+    final reddit = new Reddit.fromAuthenticator(testAuth);
+    await reddit.initialized;
+    final response =
+        await reddit.auth.get(Uri.parse('https://oauth.reddit.com/api/v1/me'));
+    expect(response['is_employee'], equals(false));
+    expect(response['name'], equals('DRAWApiOfficial'));
+    expect(response['created'], equals(1501830779.0));
+    expect(response['features'], isNot(null));
+    final features = response['features'];
+    expect(features['do_not_track'], equals(true));
+  });
+}

test/records/api_v1_me_raw.json

@@ -0,0 +1 @@
+[{"always":true,"request":["https://oauth.reddit.com/api/v1/me"],"response":{"is_employee":false,"features":{"do_not_track":true,"show_amp_link":true,"live_happening_now":true,"adserver_reporting":true,"give_hsts_grants":true,"legacy_search_pref":true,"listing_service_rampup":true,"mobile_web_targeting":true,"default_srs_holdout":{"owner":"relevance","variant":"control_2","experiment_id":171},"adzerk_do_not_track":true,"users_listing":true,"show_user_sr_name":true,"whitelisted_pms":true,"sticky_comments":true,"personalization_prefs":true,"upgrade_cookies":true,"interest_targeting":true,"new_report_flow":true,"block_user_by_report":true,"post_embed":true,"ads_auto_refund":true,"orangereds_as_emails":true,"mweb_xpromo_modal_listing_click_daily_dismissible_ios":true,"mweb_xpromo_ad_feed_android":{"owner":"channels","variant":"control_2","experiment_id":195},"expando_events":true,"eu_cookie_policy":true,"utm_comment_links":true,"force_https":true,"mobile_native_banner":true,"post_to_profile_beta":true,"reddituploads_redirect":true,"outbound_clicktracking":true,"new_loggedin_cache_policy":true,"inbox_push":true,"https_redirect":true,"search_dark_traffic":true,"mweb_xpromo_interstitial_comments_ios":true,"pause_ads":true,"programmatic_ads":true,"geopopular":true,"show_recommended_link":true,"mweb_xpromo_interstitial_comments_android":true,"ads_auction":true,"screenview_events":true,"new_report_dialog":true,"moat_tracking":true,"subreddit_rules":true,"mobile_settings":true,"adzerk_reporting_2":true,"activity_service_write":true,"ads_auto_extend":true,"geopopular_au_holdout":{"owner":"relevance","variant":"control_2","experiment_id":206},"scroll_events":true,"mweb_xpromo_modal_listing_click_daily_dismissible_android":true,"adblock_test":true,"activity_service_read":true},"pref_no_profanity":true,"is_suspended":false,"pref_geopopular":"","subreddit":null,"is_sponsor":false,"gold_expiration":null,"id":"9b8dzfo","suspension_expiration_utc":null,"verified":false,"new_modmail_exists":true,"over_18":false,"is_gold":false,"is_mod":true,"has_verified_email":false,"has_mod_mail":false,"oauth_client_id":"Db_4C6XcNCNqow","hide_from_robots":false,"link_karma":1,"inbox_count":1,"pref_top_karma_subreddits":null,"has_mail":true,"pref_show_snoovatar":false,"name":"DRAWApiOfficial","created":1501830779.0,"gold_creddits":0,"created_utc":1501801979.0,"in_beta":false,"comment_karma":0,"has_subscribed":false}}]

test/test_authenticator.dart

@@ -0,0 +1,107 @@
+// Copyright (c) 2017, the Dart Reddit API Wrapper  project authors.
+// Please see the AUTHORS file for details. All rights reserved.
+// Use of this source code is governed by a BSD-style license that
+// can be found in the LICENSE file.
+
+import 'dart:async';
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:collection/collection.dart';
+import 'package:reply/reply.dart';
+
+import 'package:draw/src/auth.dart';
+import 'package:draw/src/exceptions.dart';
+
+/// A drop-in replacement for [Authenticator], used for recording and replaying
+/// Reddit API interactions, used primarily for testing.
+class TestAuthenticator extends Authenticator {
+  final String _recordingPath;
+  final Authenticator _recordAuth;
+  final _recorder = new Recorder<List, dynamic>();
+  bool get isRecording => (_recordAuth == null);
+  Recording _recording;
+
+  /// Creates a [TestAuthenticator] object which either reads a recording from
+  /// [recordingPath] or records Reddit API requests and responses if
+  /// [recordAuth] is provided. If [recordAuth] is provided, it must be a
+  /// valid Authenticator with valid OAuth2 credentials that is capable of
+  /// making requests to the Reddit API. Note: when recording Reddit API
+  /// interactions, [writeRecording] must be called to write all prior records
+  /// to the file at [recordingPath].
+  TestAuthenticator(String recordingPath, {Authenticator recordAuth})
+      : _recordingPath = recordingPath,
+        _recordAuth = recordAuth,
+        super(null, null) {
+    if (isRecording) {
+      final rawRecording = new File(recordingPath).readAsStringSync();
+      _recording = new Recording.fromJson(JSON.decode(rawRecording),
+          toRequest: (q) => q,
+          toResponse: (r) => r,
+          requestEquality: const ListEquality());
+    }
+  }
+
+  @override
+  Future refresh() async {
+    if (isRecording) {
+      throw new DRAWAuthenticationError('cannot refresh a TestAuthenticator.');
+    }
+    return _recordAuth.refresh();
+  }
+
+  @override
+  Future revoke() async {
+    if (isRecording) {
+      throw new DRAWAuthenticationError('cannot revoke a TestAuthenticator.');
+    }
+    return _recordAuth.revoke();
+  }
+
+  @override
+  Future<Map> get(Uri path) async {
+    Map result;
+    if (isRecording) {
+      // TODO(bkonyi): grab the response based on query.
+      return _recording.reply([path.toString()]);
+    } else {
+      print(path.toString());
+      result = await _recordAuth.get(path);
+      // TODO(bkonyi): do we always want to reply?
+      _recorder.given([path.toString()]).reply(result).always();
+    }
+    return result;
+  }
+
+  @override
+  Future<Map> post(Uri path, Map<String, String> body) async {
+    Map result;
+    if (isRecording) {
+      return _recording.reply([path.toString(), body]);
+    } else {
+      print(path.toString());
+      result = await _recordAuth.post(path, body);
+      _recorder.given([path.toString(), body]).reply(result).always();
+    }
+    return result;
+  }
+
+  @override
+  bool get isValid {
+    return _recordAuth?.isValid ?? true;
+  }
+
+  /// Writes the recorded Reddit API requests and their corresponding responses
+  /// to [recordingPath] and returns a [Future<File>], which is the file that
+  /// has been written to, when in recording mode. When not in recording mode,
+  /// does nothing and returns null.
+  Future<File> writeRecording() {
+    if (!isRecording) {
+      return (new File(_recordingPath)).writeAsString(JSON
+          .encode(_recorder.toRecording().toJsonEncodable(
+              encodeRequest: (q) => q, encodeResponse: (r) => r))
+          .toString());
+    }
+    return null;
+  }
+}