Fix moving child to first position in tree data (#9761)

Resolves #9760

1 files changed, 13 insertions, 0 deletions

diff --git a/server/src/test/java/com/vaadin/data/provider/TreeDataProviderTest.java b/server/src/test/java/com/vaadin/data/provider/TreeDataProviderTest.java
index 3ff94e9988..87b3ec0715 100644
--- a/server/src/test/java/com/vaadin/data/provider/TreeDataProviderTest.java
+++ b/server/src/test/java/com/vaadin/data/provider/TreeDataProviderTest.java
@@ -123,6 +123,19 @@ public class TreeDataProviderTest
         data.moveAfterSibling(root0, null);
         Assert.assertEquals(root0, data.getRootItems().get(0));
         Assert.assertEquals(root9, data.getRootItems().get(9));
+
+        StrBean child0 = data.getChildren(root0).get(0);
+        StrBean child2 = data.getChildren(root0).get(2);
+
+        // Move first child to different position
+        data.moveAfterSibling(child0, child2);
+        Assert.assertEquals(2, data.getChildren(root0).indexOf(child0));
+        Assert.assertEquals(1, data.getChildren(root0).indexOf(child2));
+
+        // Move child back to first position
+        data.moveAfterSibling(child0, null);
+        Assert.assertEquals(0, data.getChildren(root0).indexOf(child0));
+        Assert.assertEquals(2, data.getChildren(root0).indexOf(child2));
     }
 
     @Test(expected = IllegalArgumentException.class)