ARUHA-838: Added min length for owning_application.

api/nakadi-event-bus-api.yaml

@@ -2044,6 +2044,7 @@ definitions:
         example: 'gizig'
         description: |
           The id of application owning the subscription.
+        minLength: 1
       event_types:
         type: array
         items:

src/main/java/org/zalando/nakadi/domain/SubscriptionBase.java

@@ -22,6 +22,7 @@ public enum InitialPosition {
     }
 
     @NotNull
+    @Size(min = 1, message = "must contain at least one character")
     private String owningApplication;
 
     @NotNull

src/test/java/org/zalando/nakadi/controller/PostSubscriptionControllerTest.java

@@ -145,6 +145,15 @@ public void whenCreateSubscriptionWithEmptyConsumerGroupThenUnprocessableEntity(
         checkForProblem(postSubscription(subscriptionBase), expectedProblem);
     }
 
+    @Test
+    public void whenCreateSubscriptionWithEmptyOwningApplicationThenUnprocessableEntity() throws Exception {
+        final SubscriptionBase subscriptionBase = builder()
+                .withOwningApplication("")
+                .buildSubscriptionBase();
+        final Problem expectedProblem = invalidProblem("owning_application", "must contain at least one character");
+        checkForProblem(postSubscription(subscriptionBase), expectedProblem);
+    }
+
     @Test
     public void whenOwningApplicationIsNullThenUnprocessableEntity() throws Exception {
         final SubscriptionBase subscriptionBase = builder()