100 percent test coverage achieved, patching a critical api bug in api.serializers and .views

src/apps/api/serializers.py

@@ -5,6 +5,14 @@ from apps.lyric.models import User
 
 
 class ItemSerializer(serializers.ModelSerializer):
+    text = serializers.CharField()
+
+    def validate_text(self, value):
+        list_ = self.context["list"]
+        if list_.item_set.filter(text=value).exists():
+            raise serializers.ValidationError("duplicate")
+        return value
+
     class Meta:
         model = Item
         fields = ["id", "text"]