Make response type an/single/playlist

Make it possible to assert what response to get

goutubedl_test.go

@@ -157,7 +157,7 @@ func TestPlaylist(t *testing.T) {
 	defer leakChecks(t)()
 
 	ydlResult, ydlResultErr := New(context.Background(), playlistRawURL, Options{
-		YesPlaylist:       true,
+		Type:              TypePlaylist,
 		DownloadThumbnail: false,
 	})
 
@@ -186,7 +186,7 @@ func TestPlaylistWithPrivateVideo(t *testing.T) {
 
 	playlistRawURL := "https://www.youtube.com/playlist?list=PLX0g748fkegS54oiDN4AXKl7BR7mLIydP"
 	ydlResult, ydlResultErr := New(context.Background(), playlistRawURL, Options{
-		YesPlaylist:       true,
+		Type:              TypePlaylist,
 		DownloadThumbnail: false,
 	})
 
@@ -201,20 +201,6 @@ func TestPlaylistWithPrivateVideo(t *testing.T) {
 	}
 }
 
-func TestPlaylistBadURL(t *testing.T) {
-	defer leakChecks(t)()
-
-	// using a non-playlist url
-	_, ydlResultErr := New(context.Background(), testVideoRawURL, Options{
-		YesPlaylist:       true,
-		DownloadThumbnail: false,
-	})
-
-	if ydlResultErr == nil {
-		t.Error("expected error")
-	}
-}
-
 func TestSubtitles(t *testing.T) {
 	defer leakChecks(t)()
 
@@ -246,3 +232,23 @@ func TestSubtitles(t *testing.T) {
 		}
 	}
 }
+
+func TestErrorNotAPlaylist(t *testing.T) {
+	_, ydlResultErr := New(context.Background(), testVideoRawURL, Options{
+		Type:              TypePlaylist,
+		DownloadThumbnail: false,
+	})
+	if ydlResultErr.Error() != "not a playlist" {
+		t.Errorf("expected is playlist error")
+	}
+}
+
+func TestErrorNotASingle(t *testing.T) {
+	_, ydlResultErr := New(context.Background(), playlistRawURL, Options{
+		Type:              TypeSingle,
+		DownloadThumbnail: false,
+	})
+	if ydlResultErr.Error() != "not a single" {
+		t.Errorf("expected is playlist error")
+	}
+}