diff --git a/java/src/main/java/org/softwareheritage/graph/algo/Traversal.java b/java/src/main/java/org/softwareheritage/graph/algo/Traversal.java
index 3fb08f0..0420a41 100644
--- a/java/src/main/java/org/softwareheritage/graph/algo/Traversal.java
+++ b/java/src/main/java/org/softwareheritage/graph/algo/Traversal.java
@@ -1,494 +1,494 @@
 package org.softwareheritage.graph.algo;
 
 import java.util.*;
 
 import it.unimi.dsi.bits.LongArrayBitVector;
 
 import org.softwareheritage.graph.AllowedEdges;
 import org.softwareheritage.graph.Endpoint;
 import org.softwareheritage.graph.Graph;
 import org.softwareheritage.graph.Neighbors;
 import org.softwareheritage.graph.Node;
 
 /**
  * Traversal algorithms on the compressed graph.
  * <p>
  * Internal implementation of the traversal API endpoints. These methods only input/output internal
  * long ids, which are converted in the {@link Endpoint} higher-level class to Software Heritage
  * PID.
  *
  * @author The Software Heritage developers
  * @see org.softwareheritage.graph.Endpoint
  */
 
 public class Traversal {
     /** Graph used in the traversal */
     Graph graph;
     /** Boolean to specify the use of the transposed graph */
     boolean useTransposed;
     /** Graph edge restriction */
     AllowedEdges edges;
 
     /** Hash set storing if we have visited a node */
     HashSet<Long> visited;
     /** Hash map storing parent node id for each nodes during a traversal */
     Map<Long, Long> parentNode;
     /** Number of edges accessed during traversal */
     long nbEdgesAccessed;
 
     /** random number generator, for random walks */
     Random rng;
 
     /**
      * Constructor.
      *
      * @param graph graph used in the traversal
      * @param direction a string (either "forward" or "backward") specifying edge orientation
      * @param edgesFmt a formatted string describing <a
      * href="https://docs.softwareheritage.org/devel/swh-graph/api.html#terminology">allowed edges</a>
      */
     public Traversal(Graph graph, String direction, String edgesFmt) {
         if (!direction.matches("forward|backward")) {
             throw new IllegalArgumentException("Unknown traversal direction: " + direction);
         }
 
         this.graph = graph;
         this.useTransposed = (direction.equals("backward"));
         this.edges = new AllowedEdges(graph, edgesFmt);
 
         long nbNodes = graph.getNbNodes();
         this.visited = new HashSet<>();
         this.parentNode = new HashMap<>();
         this.nbEdgesAccessed = 0;
         this.rng = new Random();
     }
 
     /**
      * Returns number of accessed edges during traversal.
      *
      * @return number of edges accessed in last traversal
      */
     public long getNbEdgesAccessed() {
         return nbEdgesAccessed;
     }
 
     /**
      * Returns number of accessed nodes during traversal.
      *
      * @return number of nodes accessed in last traversal
      */
     public long getNbNodesAccessed() {
         return this.visited.size();
     }
 
     /**
      * Push version of {@link leaves}: will fire passed callback for each leaf.
      */
     public void leavesVisitor(long srcNodeId, NodeIdConsumer cb) {
         Stack<Long> stack = new Stack<Long>();
         this.nbEdgesAccessed = 0;
 
         stack.push(srcNodeId);
         visited.add(srcNodeId);
 
         while (!stack.isEmpty()) {
             long currentNodeId = stack.pop();
 
             long neighborsCnt = 0;
             nbEdgesAccessed += graph.degree(currentNodeId, useTransposed);
             for (long neighborNodeId : new Neighbors(graph, useTransposed, edges, currentNodeId)) {
                 neighborsCnt++;
                 if (!visited.contains(neighborNodeId)) {
                     stack.push(neighborNodeId);
                     visited.add(neighborNodeId);
                 }
             }
 
             if (neighborsCnt == 0) {
                 cb.accept(currentNodeId);
             }
         }
     }
 
     /**
      * Returns the leaves of a subgraph rooted at the specified source node.
      *
      * @param srcNodeId source node
      * @return list of node ids corresponding to the leaves
      */
     public ArrayList<Long> leaves(long srcNodeId) {
         ArrayList<Long> nodeIds = new ArrayList<Long>();
         leavesVisitor(srcNodeId, (nodeId) -> nodeIds.add(nodeId));
         return nodeIds;
     }
 
     /**
      * Push version of {@link neighbors}: will fire passed callback on each
      * neighbor.
      */
     public void neighborsVisitor(long srcNodeId, NodeIdConsumer cb) {
         this.nbEdgesAccessed = graph.degree(srcNodeId, useTransposed);
         for (long neighborNodeId : new Neighbors(graph, useTransposed, edges, srcNodeId)) {
             cb.accept(neighborNodeId);
         }
     }
 
     /**
      * Returns node direct neighbors (linked with exactly one edge).
      *
      * @param srcNodeId source node
      * @return list of node ids corresponding to the neighbors
      */
     public ArrayList<Long> neighbors(long srcNodeId) {
         ArrayList<Long> nodeIds = new ArrayList<Long>();
         neighborsVisitor(srcNodeId, (nodeId) -> nodeIds.add(nodeId));
         return nodeIds;
     }
 
     /**
      * Push version of {@link visitNodes}: will fire passed callback on each
      * visited node.
      */
     public void visitNodesVisitor(long srcNodeId, NodeIdConsumer nodeCb, EdgeIdConsumer edgeCb) {
         Stack<Long> stack = new Stack<Long>();
         this.nbEdgesAccessed = 0;
 
         stack.push(srcNodeId);
         visited.add(srcNodeId);
 
         while (!stack.isEmpty()) {
             long currentNodeId = stack.pop();
             if (nodeCb != null) {
                 nodeCb.accept(currentNodeId);
             }
 
             nbEdgesAccessed += graph.degree(currentNodeId, useTransposed);
             for (long neighborNodeId : new Neighbors(graph, useTransposed, edges, currentNodeId)) {
+                if (edgeCb != null) {
+                    edgeCb.accept(currentNodeId, neighborNodeId);
+                }
                 if (!visited.contains(neighborNodeId)) {
                     stack.push(neighborNodeId);
                     visited.add(neighborNodeId);
-                    if (edgeCb != null) {
-                        edgeCb.accept(currentNodeId, neighborNodeId);
-                    }
                 }
             }
         }
     }
 
     /** One-argument version to handle callbacks properly */
     public void visitNodesVisitor(long srcNodeId, NodeIdConsumer cb) {
         visitNodesVisitor(srcNodeId, cb, null);
     }
 
     /**
      * Performs a graph traversal and returns explored nodes.
      *
      * @param srcNodeId source node
      * @return list of explored node ids
      */
     public ArrayList<Long> visitNodes(long srcNodeId) {
         ArrayList<Long> nodeIds = new ArrayList<Long>();
         visitNodesVisitor(srcNodeId, (nodeId) -> nodeIds.add(nodeId));
         return nodeIds;
     }
 
     /**
      * Push version of {@link visitPaths}: will fire passed callback on each
      * discovered (complete) path.
      */
     public void visitPathsVisitor(long srcNodeId, PathConsumer cb) {
         Stack<Long> currentPath = new Stack<Long>();
         this.nbEdgesAccessed = 0;
         visitPathsInternalVisitor(srcNodeId, currentPath, cb);
     }
 
     /**
      * Performs a graph traversal and returns explored paths.
      *
      * @param srcNodeId source node
      * @return list of explored paths (represented as a list of node ids)
      */
     public ArrayList<ArrayList<Long>> visitPaths(long srcNodeId) {
         ArrayList<ArrayList<Long>> paths = new ArrayList<>();
         visitPathsVisitor(srcNodeId, (path) -> paths.add(path));
         return paths;
     }
 
     private void visitPathsInternalVisitor(long currentNodeId,
                                            Stack<Long> currentPath,
                                            PathConsumer cb) {
         currentPath.push(currentNodeId);
 
         long visitedNeighbors = 0;
         nbEdgesAccessed += graph.degree(currentNodeId, useTransposed);
         for (long neighborNodeId : new Neighbors(graph, useTransposed, edges, currentNodeId)) {
             visitPathsInternalVisitor(neighborNodeId, currentPath, cb);
             visitedNeighbors++;
         }
 
         if (visitedNeighbors == 0) {
             ArrayList<Long> path = new ArrayList<Long>();
             for (long nodeId : currentPath) {
                 path.add(nodeId);
             }
             cb.accept(path);
         }
 
         currentPath.pop();
     }
 
     /**
      * Performs a graph traversal with backtracking, and returns the first
      * found path from source to destination.
      *
      * @param srcNodeId source node
      * @param dst destination (either a node or a node type)
      * @return found path as a list of node ids
      */
     public <T> ArrayList<Long> walk(long srcNodeId, T dst, String visitOrder) {
         long dstNodeId = -1;
         if (visitOrder.equals("dfs")) {
             dstNodeId = walkInternalDFS(srcNodeId, dst);
         } else if (visitOrder.equals("bfs")) {
             dstNodeId = walkInternalBFS(srcNodeId, dst);
         } else {
             throw new IllegalArgumentException("Unknown visit order: " + visitOrder);
         }
 
         if (dstNodeId == -1) {
             throw new IllegalArgumentException("Cannot find destination: " + dst);
         }
 
         ArrayList<Long> nodeIds = backtracking(srcNodeId, dstNodeId);
         return nodeIds;
     }
 
     /**
      * Performs a random walk (picking a random successor at each step) from
      * source to destination.
      *
      * @param srcNodeId source node
      * @param dst destination (either a node or a node type)
      * @return found path as a list of node ids or an empty path to indicate
      * that no suitable path have been found
      */
     public <T> ArrayList<Long> randomWalk(long srcNodeId, T dst) {
         return randomWalk(srcNodeId, dst, 0);
     }
 
     /**
      * Performs a stubborn random walk (picking a random successor at each
      * step) from source to destination. The walk is "stubborn" in the sense
      * that it will not give up the first time if a satisfying target node is
      * found, but it will retry up to a limited amount of times.
      *
      * @param srcNodeId source node
      * @param dst destination (either a node or a node type)
      * @param retries number of times to retry; 0 means no retries (single walk)
      * @return found path as a list of node ids or an empty path to indicate
      * that no suitable path have been found
      */
     public <T> ArrayList<Long> randomWalk(long srcNodeId, T dst, int retries) {
         long curNodeId = srcNodeId;
         ArrayList<Long> path = new ArrayList<Long>();
         this.nbEdgesAccessed = 0;
         boolean found;
 
         if (retries < 0) {
             throw new IllegalArgumentException("Negative number of retries given: " + retries);
         }
 
         while (true) {
             path.add(curNodeId);
             Neighbors neighbors = new Neighbors(graph, useTransposed, edges, curNodeId);
             curNodeId = randomPick(neighbors.iterator());
             if (curNodeId < 0) {
                 found = false;
                 break;
             }
             if (isDstNode(curNodeId, dst)) {
                 path.add(curNodeId);
                 found = true;
                 break;
             }
         }
 
         if (found) {
             return path;
         } else if (retries > 0) {  // try again
             return randomWalk(srcNodeId, dst, retries - 1);
         } else {  // not found and no retries left
             path.clear();
             return path;
         }
     }
 
     /**
      * Randomly choose an element from an iterator over Longs using reservoir
      * sampling
      *
      * @param elements iterator over selection domain
      * @return randomly chosen element or -1 if no suitable element was found
      */
     private long randomPick(Iterator<Long> elements) {
         long curPick = -1;
         long seenCandidates = 0;
 
         while (elements.hasNext()) {
             seenCandidates++;
             if (Math.round(rng.nextFloat() * (seenCandidates - 1)) == 0) {
                 curPick = elements.next();
             }
         }
 
         return curPick;
     }
 
     /**
      * Internal DFS function of {@link #walk}.
      *
      * @param srcNodeId source node
      * @param dst destination (either a node or a node type)
      * @return final destination node or -1 if no path found
      */
     private <T> long walkInternalDFS(long srcNodeId, T dst) {
         Stack<Long> stack = new Stack<Long>();
         this.nbEdgesAccessed = 0;
 
         stack.push(srcNodeId);
         visited.add(srcNodeId);
 
         while (!stack.isEmpty()) {
             long currentNodeId = stack.pop();
             if (isDstNode(currentNodeId, dst)) {
                 return currentNodeId;
             }
 
             nbEdgesAccessed += graph.degree(currentNodeId, useTransposed);
             for (long neighborNodeId : new Neighbors(graph, useTransposed, edges, currentNodeId)) {
                 if (!visited.contains(neighborNodeId)) {
                     stack.push(neighborNodeId);
                     visited.add(neighborNodeId);
                     parentNode.put(neighborNodeId, currentNodeId);
                 }
             }
         }
 
         return -1;
     }
 
     /**
      * Internal BFS function of {@link #walk}.
      *
      * @param srcNodeId source node
      * @param dst destination (either a node or a node type)
      * @return final destination node or -1 if no path found
      */
     private <T> long walkInternalBFS(long srcNodeId, T dst) {
         Queue<Long> queue = new LinkedList<Long>();
         this.nbEdgesAccessed = 0;
 
         queue.add(srcNodeId);
         visited.add(srcNodeId);
 
         while (!queue.isEmpty()) {
             long currentNodeId = queue.poll();
             if (isDstNode(currentNodeId, dst)) {
                 return currentNodeId;
             }
 
             nbEdgesAccessed += graph.degree(currentNodeId, useTransposed);
             for (long neighborNodeId : new Neighbors(graph, useTransposed, edges, currentNodeId)) {
                 if (!visited.contains(neighborNodeId)) {
                     queue.add(neighborNodeId);
                     visited.add(neighborNodeId);
                     parentNode.put(neighborNodeId, currentNodeId);
                 }
             }
         }
 
         return -1;
     }
 
     /**
      * Internal function of {@link #walk} to check if a node corresponds to the destination.
      *
      * @param nodeId current node
      * @param dst destination (either a node or a node type)
      * @return true if the node is a destination, or false otherwise
      */
     private <T> boolean isDstNode(long nodeId, T dst) {
         if (dst instanceof Long) {
             long dstNodeId = (Long) dst;
             return nodeId == dstNodeId;
         } else if (dst instanceof Node.Type) {
             Node.Type dstType = (Node.Type) dst;
             return graph.getNodeType(nodeId) == dstType;
         } else {
             return false;
         }
     }
 
     /**
      * Internal backtracking function of {@link #walk}.
      *
      * @param srcNodeId source node
      * @param dstNodeId destination node
      * @return the found path, as a list of node ids
      */
     private ArrayList<Long> backtracking(long srcNodeId, long dstNodeId) {
         ArrayList<Long> path = new ArrayList<Long>();
         long currentNodeId = dstNodeId;
         while (currentNodeId != srcNodeId) {
             path.add(currentNodeId);
             currentNodeId = parentNode.get(currentNodeId);
         }
         path.add(srcNodeId);
         Collections.reverse(path);
         return path;
     }
 
     public Long findCommonDescendant(long lhsNode, long rhsNode) {
         Queue<Long> lhsStack = new ArrayDeque<>();
         Queue<Long> rhsStack = new ArrayDeque<>();
         HashSet<Long> lhsVisited = new HashSet<>();
         HashSet<Long> rhsVisited = new HashSet<>();
         lhsStack.add(lhsNode);
         rhsStack.add(rhsNode);
         lhsVisited.add(lhsNode);
         rhsVisited.add(rhsNode);
 
         this.nbEdgesAccessed = 0;
         Long curNode;
 
         while (!lhsStack.isEmpty() || !rhsStack.isEmpty()) {
             if (!lhsStack.isEmpty()) {
                 curNode = lhsStack.poll();
                 nbEdgesAccessed += graph.degree(curNode, useTransposed);
                 for (long neighborNodeId : new Neighbors(graph, useTransposed, edges, curNode)) {
                     if (!lhsVisited.contains(neighborNodeId)) {
                         if (rhsVisited.contains(neighborNodeId))
                             return neighborNodeId;
                         lhsStack.add(neighborNodeId);
                         lhsVisited.add(neighborNodeId);
                     }
                 }
             }
 
             if (!rhsStack.isEmpty()) {
                 curNode = rhsStack.poll();
                 nbEdgesAccessed += graph.degree(curNode, useTransposed);
                 for (long neighborNodeId : new Neighbors(graph, useTransposed, edges, curNode)) {
                     if (!rhsVisited.contains(neighborNodeId)) {
                         if (lhsVisited.contains(neighborNodeId))
                             return neighborNodeId;
                         rhsStack.add(neighborNodeId);
                         rhsVisited.add(neighborNodeId);
                     }
                 }
             }
         }
 
         return null;
     }
 }
diff --git a/swh/graph/tests/test_api_client.py b/swh/graph/tests/test_api_client.py
index 642cf6e..96279d0 100644
--- a/swh/graph/tests/test_api_client.py
+++ b/swh/graph/tests/test_api_client.py
@@ -1,258 +1,305 @@
 import pytest
 
 
 from pytest import raises
 
 from swh.core.api import RemoteException
 
 
 def test_stats(graph_client):
     stats = graph_client.stats()
 
     assert set(stats.keys()) == {"counts", "ratios", "indegree", "outdegree"}
 
     assert set(stats["counts"].keys()) == {"nodes", "edges"}
     assert set(stats["ratios"].keys()) == {
         "compression",
         "bits_per_node",
         "bits_per_edge",
         "avg_locality",
     }
     assert set(stats["indegree"].keys()) == {"min", "max", "avg"}
     assert set(stats["outdegree"].keys()) == {"min", "max", "avg"}
 
     assert stats["counts"]["nodes"] == 21
     assert stats["counts"]["edges"] == 23
     assert isinstance(stats["ratios"]["compression"], float)
     assert isinstance(stats["ratios"]["bits_per_node"], float)
     assert isinstance(stats["ratios"]["bits_per_edge"], float)
     assert isinstance(stats["ratios"]["avg_locality"], float)
     assert stats["indegree"]["min"] == 0
     assert stats["indegree"]["max"] == 3
     assert isinstance(stats["indegree"]["avg"], float)
     assert stats["outdegree"]["min"] == 0
     assert stats["outdegree"]["max"] == 3
     assert isinstance(stats["outdegree"]["avg"], float)
 
 
 def test_leaves(graph_client):
     actual = list(
         graph_client.leaves("swh:1:ori:0000000000000000000000000000000000000021")
     )
     expected = [
         "swh:1:cnt:0000000000000000000000000000000000000001",
         "swh:1:cnt:0000000000000000000000000000000000000004",
         "swh:1:cnt:0000000000000000000000000000000000000005",
         "swh:1:cnt:0000000000000000000000000000000000000007",
     ]
     assert set(actual) == set(expected)
 
 
 def test_neighbors(graph_client):
     actual = list(
         graph_client.neighbors(
             "swh:1:rev:0000000000000000000000000000000000000009", direction="backward"
         )
     )
     expected = [
         "swh:1:snp:0000000000000000000000000000000000000020",
         "swh:1:rel:0000000000000000000000000000000000000010",
         "swh:1:rev:0000000000000000000000000000000000000013",
     ]
     assert set(actual) == set(expected)
 
 
 def test_visit_nodes(graph_client):
     actual = list(
         graph_client.visit_nodes(
             "swh:1:rel:0000000000000000000000000000000000000010",
             edges="rel:rev,rev:rev",
         )
     )
     expected = [
         "swh:1:rel:0000000000000000000000000000000000000010",
         "swh:1:rev:0000000000000000000000000000000000000009",
         "swh:1:rev:0000000000000000000000000000000000000003",
     ]
     assert set(actual) == set(expected)
 
 
 def test_visit_edges(graph_client):
     actual = list(
         graph_client.visit_edges(
             "swh:1:rel:0000000000000000000000000000000000000010",
             edges="rel:rev,rev:rev,rev:dir",
         )
     )
     expected = [
         (
             "swh:1:rel:0000000000000000000000000000000000000010",
             "swh:1:rev:0000000000000000000000000000000000000009",
         ),
         (
             "swh:1:rev:0000000000000000000000000000000000000009",
             "swh:1:rev:0000000000000000000000000000000000000003",
         ),
         (
             "swh:1:rev:0000000000000000000000000000000000000009",
             "swh:1:dir:0000000000000000000000000000000000000008",
         ),
         (
             "swh:1:rev:0000000000000000000000000000000000000003",
             "swh:1:dir:0000000000000000000000000000000000000002",
         ),
     ]
     assert set(actual) == set(expected)
 
 
+def test_visit_edges_diamond_pattern(graph_client):
+    actual = list(
+        graph_client.visit_edges(
+            "swh:1:rev:0000000000000000000000000000000000000009", edges="*",
+        )
+    )
+    expected = [
+        (
+            "swh:1:rev:0000000000000000000000000000000000000009",
+            "swh:1:rev:0000000000000000000000000000000000000003",
+        ),
+        (
+            "swh:1:rev:0000000000000000000000000000000000000009",
+            "swh:1:dir:0000000000000000000000000000000000000008",
+        ),
+        (
+            "swh:1:rev:0000000000000000000000000000000000000003",
+            "swh:1:dir:0000000000000000000000000000000000000002",
+        ),
+        (
+            "swh:1:dir:0000000000000000000000000000000000000002",
+            "swh:1:cnt:0000000000000000000000000000000000000001",
+        ),
+        (
+            "swh:1:dir:0000000000000000000000000000000000000008",
+            "swh:1:cnt:0000000000000000000000000000000000000001",
+        ),
+        (
+            "swh:1:dir:0000000000000000000000000000000000000008",
+            "swh:1:cnt:0000000000000000000000000000000000000007",
+        ),
+        (
+            "swh:1:dir:0000000000000000000000000000000000000008",
+            "swh:1:dir:0000000000000000000000000000000000000006",
+        ),
+        (
+            "swh:1:dir:0000000000000000000000000000000000000006",
+            "swh:1:cnt:0000000000000000000000000000000000000004",
+        ),
+        (
+            "swh:1:dir:0000000000000000000000000000000000000006",
+            "swh:1:cnt:0000000000000000000000000000000000000005",
+        ),
+    ]
+    assert set(actual) == set(expected)
+
+
 def test_visit_paths(graph_client):
     actual = list(
         graph_client.visit_paths(
             "swh:1:snp:0000000000000000000000000000000000000020", edges="snp:*,rev:*"
         )
     )
     actual = [tuple(path) for path in actual]
     expected = [
         (
             "swh:1:snp:0000000000000000000000000000000000000020",
             "swh:1:rev:0000000000000000000000000000000000000009",
             "swh:1:rev:0000000000000000000000000000000000000003",
             "swh:1:dir:0000000000000000000000000000000000000002",
         ),
         (
             "swh:1:snp:0000000000000000000000000000000000000020",
             "swh:1:rev:0000000000000000000000000000000000000009",
             "swh:1:dir:0000000000000000000000000000000000000008",
         ),
         (
             "swh:1:snp:0000000000000000000000000000000000000020",
             "swh:1:rel:0000000000000000000000000000000000000010",
         ),
     ]
     assert set(actual) == set(expected)
 
 
 @pytest.mark.skip(reason="currently disabled due to T1969")
 def test_walk(graph_client):
     args = ("swh:1:dir:0000000000000000000000000000000000000016", "rel")
     kwargs = {
         "edges": "dir:dir,dir:rev,rev:*",
         "direction": "backward",
         "traversal": "bfs",
     }
 
     actual = list(graph_client.walk(*args, **kwargs))
     expected = [
         "swh:1:dir:0000000000000000000000000000000000000016",
         "swh:1:dir:0000000000000000000000000000000000000017",
         "swh:1:rev:0000000000000000000000000000000000000018",
         "swh:1:rel:0000000000000000000000000000000000000019",
     ]
     assert set(actual) == set(expected)
 
     kwargs2 = kwargs.copy()
     kwargs2["limit"] = -1
     actual = list(graph_client.walk(*args, **kwargs2))
     expected = ["swh:1:rel:0000000000000000000000000000000000000019"]
     assert set(actual) == set(expected)
 
     kwargs2 = kwargs.copy()
     kwargs2["limit"] = 2
     actual = list(graph_client.walk(*args, **kwargs2))
     expected = [
         "swh:1:dir:0000000000000000000000000000000000000016",
         "swh:1:dir:0000000000000000000000000000000000000017",
     ]
     assert set(actual) == set(expected)
 
 
 def test_random_walk(graph_client):
     """as the walk is random, we test a visit from a cnt node to the only origin in
     the dataset, and only check the final node of the path (i.e., the origin)
 
     """
     args = ("swh:1:cnt:0000000000000000000000000000000000000001", "ori")
     kwargs = {"direction": "backward"}
     expected_root = "swh:1:ori:0000000000000000000000000000000000000021"
 
     actual = list(graph_client.random_walk(*args, **kwargs))
     assert len(actual) > 1  # no origin directly links to a content
     assert actual[0] == args[0]
     assert actual[-1] == expected_root
 
     kwargs2 = kwargs.copy()
     kwargs2["limit"] = -1
     actual = list(graph_client.random_walk(*args, **kwargs2))
     assert actual == [expected_root]
 
     kwargs2["limit"] = -2
     actual = list(graph_client.random_walk(*args, **kwargs2))
     assert len(actual) == 2
     assert actual[-1] == expected_root
 
     kwargs2["limit"] = 3
     actual = list(graph_client.random_walk(*args, **kwargs2))
     assert len(actual) == 3
 
 
 def test_count(graph_client):
     actual = graph_client.count_leaves(
         "swh:1:ori:0000000000000000000000000000000000000021"
     )
     assert actual == 4
     actual = graph_client.count_visit_nodes(
         "swh:1:rel:0000000000000000000000000000000000000010", edges="rel:rev,rev:rev"
     )
     assert actual == 3
     actual = graph_client.count_neighbors(
         "swh:1:rev:0000000000000000000000000000000000000009", direction="backward"
     )
     assert actual == 3
 
 
 def test_param_validation(graph_client):
     with raises(RemoteException) as exc_info:  # PID not found
         list(graph_client.leaves("swh:1:ori:fff0000000000000000000000000000000000021"))
     assert exc_info.value.response.status_code == 404
 
     with raises(RemoteException) as exc_info:  # malformed PID
         list(
             graph_client.neighbors("swh:1:ori:fff000000zzzzzz0000000000000000000000021")
         )
     assert exc_info.value.response.status_code == 400
 
     with raises(RemoteException) as exc_info:  # malformed edge specificaiton
         list(
             graph_client.visit_nodes(
                 "swh:1:dir:0000000000000000000000000000000000000016",
                 edges="dir:notanodetype,dir:rev,rev:*",
                 direction="backward",
             )
         )
     assert exc_info.value.response.status_code == 400
 
     with raises(RemoteException) as exc_info:  # malformed direction
         list(
             graph_client.visit_nodes(
                 "swh:1:dir:0000000000000000000000000000000000000016",
                 edges="dir:dir,dir:rev,rev:*",
                 direction="notadirection",
             )
         )
     assert exc_info.value.response.status_code == 400
 
 
 @pytest.mark.skip(reason="currently disabled due to T1969")
 def test_param_validation_walk(graph_client):
     """test validation of walk-specific parameters only"""
     with raises(RemoteException) as exc_info:  # malformed traversal order
         list(
             graph_client.walk(
                 "swh:1:dir:0000000000000000000000000000000000000016",
                 "rel",
                 edges="dir:dir,dir:rev,rev:*",
                 direction="backward",
                 traversal="notatraversalorder",
             )
         )
     assert exc_info.value.response.status_code == 400