Implement more tests

Close #47

lib/src/videos/video_client.dart

@@ -51,7 +51,12 @@ class VideoClient {
 
   Future<Video> _getVideoFromFixPlaylist(VideoId id) async {
     var playlistInfo = await PlaylistResponse.get(_httpClient, 'RD${id.value}');
-    var video = playlistInfo.videos.firstWhere((e) => e.id == id.value);
+
+    var video = playlistInfo.videos
+        .firstWhere((e) => e.id == id.value, orElse: () => null);
+    if (video == null) {
+      throw TransientFailureException('Video not found in mix playlist');
+    }
 
     return Video(
         id,

test/channel_test.dart

@@ -18,7 +18,7 @@ void main() {
       var channel = await yt.channels.get(ChannelId(channelUrl));
       expect(channel.url, channelUrl);
       expect(channel.title, 'Tyrrrz');
-      expect(channel.logoUrl, isNotNull);
+      expect(channel.logoUrl, isNotEmpty);
       expect(channel.logoUrl, isNot(equalsIgnoringWhitespace('')));
     });
 
@@ -70,5 +70,13 @@ void main() {
           .toList();
       expect(videos, isNotEmpty);
     });
+
+    test('GetVideosOfYoutubeChannelFromUploadPage', () async {
+      var videos = await yt.channels
+          .getUploadsFromPage('UCEnBXANsKmyj2r9xVyKoDiQ')
+          .take(30)
+          .toList();
+      expect(videos, hasLength(30));
+    });
   });
 }

test/closed_caption_test.dart

@@ -33,8 +33,8 @@ void main() {
       var captionPart =
           caption.getPartByTime(const Duration(milliseconds: 650));
 
-      expect(caption, isNotNull);
-      expect(captionPart, isNotNull);
+      expect(caption, isNotEmpty);
+      expect(captionPart, isNotEmpty);
       expect(caption.text, 'know I worked really hard on not doing');
       expect(captionPart.text, ' hard');
     });

test/playlist_test.dart

@@ -24,6 +24,11 @@ void main() {
       expect(playlist.engagement.viewCount, greaterThanOrEqualTo(133));
       expect(playlist.engagement.likeCount, greaterThanOrEqualTo(0));
       expect(playlist.engagement.dislikeCount, greaterThanOrEqualTo(0));
+      expect(playlist.thumbnails.lowResUrl, isNotEmpty);
+      expect(playlist.thumbnails.mediumResUrl, isNotEmpty);
+      expect(playlist.thumbnails.highResUrl, isNotEmpty);
+      expect(playlist.thumbnails.standardResUrl, isNotEmpty);
+      expect(playlist.thumbnails.maxResUrl, isNotEmpty);
     });
     test('GetMetadataOfAnyPlaylist', () async {
       var data = {

test/video_test.dart

@@ -18,16 +18,17 @@ void main() {
       expect(video.id.value, 'AI7ULzgf8RU');
       expect(video.url, videoUrl);
       expect(video.title, 'Aka no Ha [Another] +HDHR');
+      expect(video.channelId.value, 'UCEnBXANsKmyj2r9xVyKoDiQ');
       expect(video.author, 'Tyrrrz');
-      expect(video.uploadDate, DateTime(2017, 09, 30));
+      expect(video.uploadDate, DateTime(2017, 09, 30, 19, 15, 26));
       expect(video.description, contains('246pp'));
-      expect(video.duration, const Duration(minutes: 1, seconds: 48));
-      expect(video.thumbnails.lowResUrl, isNotNull);
-      expect(video.thumbnails.mediumResUrl, isNotNull);
-      expect(video.thumbnails.highResUrl, isNotNull);
-      expect(video.thumbnails.standardResUrl, isNotNull);
-      expect(video.thumbnails.maxResUrl, isNotNull);
-      expect(video.keywords, orderedEquals(['osu', 'mouse', 'rhythm game']));
+      expect(video.duration, const Duration(minutes: 1, seconds: 49));
+      expect(video.thumbnails.lowResUrl, isNotEmpty);
+      expect(video.thumbnails.mediumResUrl, isNotEmpty);
+      expect(video.thumbnails.highResUrl, isNotEmpty);
+      expect(video.thumbnails.standardResUrl, isNotEmpty);
+      expect(video.thumbnails.maxResUrl, isNotEmpty);
+      expect(video.keywords, orderedEquals(['osu', 'mouse', '"rhythm game"']));
       expect(video.engagement.viewCount, greaterThanOrEqualTo(134));
       expect(video.engagement.likeCount, greaterThanOrEqualTo(5));
       expect(video.engagement.dislikeCount, greaterThanOrEqualTo(0));