add Test for forEachAncestor

Author: lennart

src/main/java/com/thealgorithms/tree/CentroidDecomposition.java

@@ -162,7 +162,7 @@ public void findCentroid(int src, int previousCentroid){
      * Applies the given action to all centroid ancestors of the given node,
      * including the node itself, walking up via centroidParent[] until the root.
      */
-    public void forEachAcestor(int centroid, IntConsumer action){
+    public void forEachAncestor(int centroid, IntConsumer action){
         int curr = centroid;
         while(curr != -1){
             action.accept(curr);

src/test/java/com/thealgorithms/tree/CentroidDecompositionTest.java

@@ -174,6 +174,30 @@ void resetClearsCentroidData() {
         assertEquals(0, cd.getParent(11));
     }
 
+
+    @Test
+    void forEachAncestorVisitsCorrectChain() {
+        cd.build();
+
+        int[] testNodes = {0, 3, 7, 11, 15};
+
+        for (int node : testNodes) {
+
+            List<Integer> visited = new ArrayList<>();
+            cd.forEachAncestor(node, visited::add);
+
+            List<Integer> expected = new ArrayList<>();
+            int curr = node;
+            while (curr != -1) {
+                expected.add(curr);
+                curr = cd.getParent(curr);
+            }
+
+            assertEquals(expected, visited,
+                "forEachAncestor wrong for node " + node);
+        }
+    }
+
     @Test
     void buildingFromDifferentStartNodesYieldsValidTrees() {
         CentroidDecomposition a = new CentroidDecomposition(16, 0);