Update `create team` mutation signature

client/src/graphql/gql/mutations/createTeam.gql

@@ -1,9 +1,14 @@
 #import "gql/fragments/teamParts.gql"
 mutation CreateTeamMutation($input: CreateTeamInput!) {
   createTeam(input: $input) {
-    success
-    team {
-      ...TeamParts
+    result {
+      __typename
+      ...on TeamNode {
+        ...TeamParts
+      }
+      ...on DuplicateName {
+        reason
+      }
     }
   }
 }

server/schema.graphql

@@ -367,11 +367,12 @@ input CreateTeamInput {
 }
 
 type CreateTeamPayload {
-  success: Boolean
-  team: TeamNode
+  result: CreateTeamResult
   clientMutationId: String
 }
 
+union CreateTeamResult = TeamNode | DuplicateName
+
 scalar Date
 
 scalar DateTime

server/users/schema/mutations.py

@@ -10,12 +10,13 @@ from api.utils import get_object
 from core.logger import get_logger
 from users.inputs import PasswordUpdateInput
 from users.models import SchoolClass, SchoolClassMember, Team
-from users.schema import SchoolClassNode, TeamNode, UpdateError, FieldError, CreateSchoolClassResult
+from users.schema import CreateSchoolClassResult, CreateTeamResult, FieldError, SchoolClassNode, TeamNode, UpdateError
 from users.serializers import AvatarUrlSerializer, PasswordSerialzer
 
-
 logger = get_logger(__name__)
 
+DUPLICATE_REASON = {"reason": "Dieser Name wird bereits verwendet."}
+
 
 class CodeNotFoundException(Exception):
     pass
@@ -210,26 +211,28 @@ class CreateSchoolClass(TeacherOnlyMutation):
             user.set_selected_class(school_class)
             return cls(result=school_class)
         except IntegrityError:
-            return cls(result={"reason": "Dieser Name wird bereits verwendet."})
+            return cls(result=DUPLICATE_REASON)
 
 
 class CreateTeam(TeacherOnlyMutation):
     class Input:
         name = graphene.String(required=True)
 
-    success = graphene.Boolean()
-    team = graphene.Field(TeamNode)
+    result = CreateTeamResult()
 
     @classmethod
     def mutate_and_get_payload(cls, root, info, **kwargs):
         name = kwargs.get('name')
         user = info.context.user
 
-        team = Team.objects.create(name=name, creator=user)
-        team.generate_code()
-        user.team = team
-        user.save()
-        return cls(success=True, team=team)
+        try:
+            team = Team.objects.create(name=name, creator=user)
+            team.generate_code()
+            user.team = team
+            user.save()
+            return cls(result=team)
+        except IntegrityError:
+            return cls(result=DUPLICATE_REASON)
 
 
 class UpdateTeam(TeacherOnlyMutation):

server/users/schema/types.py

@@ -186,6 +186,17 @@ class DuplicateName(graphene.ObjectType):
     reason = graphene.String()
 
 
+class CreateTeamResult(graphene.Union):
+    class Meta:
+        types = (TeamNode, DuplicateName)
+
+    @classmethod
+    def resolve_type(cls, instance, info):
+        if type(instance).__name__ == "Team":
+            return TeamNode
+        return DuplicateName
+
+
 class CreateSchoolClassResult(graphene.Union):
     class Meta:
         types = (SchoolClassNode, DuplicateName)

server/users/tests/test_teams.py

@@ -101,22 +101,33 @@ class TeamTest(TestCase):
         self.join_team(second_team.code, context)
         self.check_me(context, second_team.name, second_team.code)
 
-    def test_create_team_mutation(self):
-        team_name = "Dunder Mifflin"
+    def _get_team_mutation_result(self, name):
         variables = {
             "input": {
-                "name": team_name
+                "name": name
             }
         }
         result = self.client.execute(CREATE_TEAM_MUTATION, context=self.context, variables=variables)
         self.no_error(result)
         create_team = result.get('data').get('createTeam')
-        team = create_team.get('team')
-        success = create_team.get('success')
-        self.assertTrue(success)
+        result = create_team.get('result')
+        typename = result.get('__typename')
+        return result, typename
+
+    def test_create_team_mutation_success(self):
+        team_name = "Dunder Mifflin"
+        team, typename = self._get_team_mutation_result(team_name)
+        self.assertEqual(typename, 'TeamNode')
         self.assertEqual(team.get('name'), team_name)
         self.assertIsNotNone(team.get('code'))
 
+    def test_create_team_mutation_fail_duplicate_name(self):
+        team_name = "Dunder Mifflin"
+        Team.objects.create(name=team_name)
+        duplicate_name, typename = self._get_team_mutation_result(team_name)
+        self.assertEqual(typename, 'DuplicateName')
+        self.assertEqual(duplicate_name.get('reason'), 'Dieser Name wird bereits verwendet.')
+
     def test_update_team_name(self):
         new_name = 'Team Böhmermann'
         variables = {
@@ -149,7 +160,7 @@ class TeamTest(TestCase):
         context = Context(user=schelm)
         team = Team.objects.get(pk=self.team.pk)
         old_name = team.name
-        self.assertFalse(self.team.members.filter(pk=schelm.pk).exists()) 
+        self.assertFalse(self.team.members.filter(pk=schelm.pk).exists())
         variables = {
             "input": {
                 "name": 'Not gonna happen',
@@ -199,4 +210,3 @@ class TeamTest(TestCase):
 
         student_after = User.objects.get(pk=self.student.pk)
         self.assertIsNone(student_after.team)
-