Node.setName(): ensure that setting name to null enables the name supplier

src/main/java/net/kemitix/node/Node.java

@@ -22,7 +22,8 @@ public interface Node<T> {
     String getName();
 
     /**
-     * Sets the explicit name for a node.
+     * Sets the explicit name for a node. Setting the name to null will clear
+     * the name and revert to the parent's name supplier.
      *
      * @param name the new name
      */

src/test/java/net/kemitix/node/NodeItemTest.java

@@ -975,6 +975,18 @@ public class NodeItemTest {
         assertThat(child.getName()).isEqualTo("local supplier");
     }
 
+    @Test
+    public void setNameToNullRevertsToParentNameSupplier() {
+        //given
+        node = new NodeItem<>(null, n -> "root supplier");
+        val child = new NodeItem<String>(null, "child name", node);
+        assertThat(child.getName()).isEqualTo("child name");
+        //when
+        child.setName(null);
+        //then
+        assertThat(child.getName()).isEqualTo("root supplier");
+    }
+
     @Test
     public void getNameWithNameSupplierIsRecalculatedEachCall() {
         val counter = new AtomicInteger(0);