diff --git a/src/main/java/org/cqfn/astranaut/core/algorithms/NodeAllocator.java b/src/main/java/org/cqfn/astranaut/core/algorithms/NodeAllocator.java
index 5a0e310..67a283b 100644
--- a/src/main/java/org/cqfn/astranaut/core/algorithms/NodeAllocator.java
+++ b/src/main/java/org/cqfn/astranaut/core/algorithms/NodeAllocator.java
@@ -130,7 +130,6 @@ private boolean fullMapping(final Node[] destination, final List<Node> source) {
                 break;
             }
             result = this.bindAllNodes(destination, array);
-            assert !result || this.required.getCount() == 0;
         } while (false);
         return result;
     }
diff --git a/src/test/java/org/cqfn/astranaut/core/algorithms/LabeledTreeBuilderTest.java b/src/test/java/org/cqfn/astranaut/core/algorithms/LabeledTreeBuilderTest.java
index d0f53cc..89b757c 100644
--- a/src/test/java/org/cqfn/astranaut/core/algorithms/LabeledTreeBuilderTest.java
+++ b/src/test/java/org/cqfn/astranaut/core/algorithms/LabeledTreeBuilderTest.java
@@ -26,6 +26,7 @@
 import java.util.Collections;
 import java.util.Optional;
 import org.cqfn.astranaut.core.base.Node;
+import org.cqfn.astranaut.core.base.PrototypeBasedNode;
 import org.cqfn.astranaut.core.base.Tree;
 import org.cqfn.astranaut.core.example.LittleTrees;
 import org.junit.jupiter.api.Assertions;
@@ -51,5 +52,8 @@ void testBaseMethods() {
             .findFirst(node -> node.getTypeName().equals(target.getTypeName()));
         Assertions.assertTrue(colored.isPresent());
         Assertions.assertEquals(colored.get().getProperties().get(name), value);
+        final Node root = labeled.getRoot();
+        Assertions.assertTrue(root instanceof PrototypeBasedNode);
+        Assertions.assertSame(((PrototypeBasedNode) root).getPrototype(), original);
     }
 }