Index: trunk/test/unit/org/openstreetmap/josm/actions/CombineWayActionTest.java
===================================================================
--- trunk/test/unit/org/openstreetmap/josm/actions/CombineWayActionTest.java	(revision 8856)
+++ trunk/test/unit/org/openstreetmap/josm/actions/CombineWayActionTest.java	(revision 8856)
@@ -0,0 +1,57 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.actions;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.openstreetmap.josm.JOSMFixture;
+import org.openstreetmap.josm.TestUtils;
+import org.openstreetmap.josm.actions.CombineWayAction.NodeGraph;
+import org.openstreetmap.josm.data.osm.DataSet;
+import org.openstreetmap.josm.data.osm.Node;
+import org.openstreetmap.josm.io.IllegalDataException;
+import org.openstreetmap.josm.io.OsmReader;
+
+/**
+ * Unit tests for class CombineWayAction.
+ */
+public class CombineWayActionTest {
+
+    /**
+     * Setup test.
+     */
+    @BeforeClass
+    public static void setUp() {
+        JOSMFixture.createUnitTestFixture().init(false);
+    }
+
+    /**
+     * Non-regression test for bug #11957.
+     * @throws IOException if any I/O error occurs
+     * @throws IllegalDataException if OSM parsing fails
+     */
+    @Test
+    public void testTicket11957() throws IOException, IllegalDataException {
+        try (InputStream is = new FileInputStream(TestUtils.getRegressionDataFile(11957, "data.osm"))) {
+            DataSet ds = OsmReader.parseDataSet(is, null);
+            NodeGraph graph = NodeGraph.createNearlyUndirectedGraphFromNodeWays(ds.getWays());
+            List<Node> path = graph.buildSpanningPath();
+            assertEquals(10, path.size());
+            Set<Long> firstAndLastObtained = new HashSet<>();
+            firstAndLastObtained.add(path.get(0).getId());
+            firstAndLastObtained.add(path.get(path.size()-1).getId());
+            Set<Long> firstAndLastExpected = new HashSet<>();
+            firstAndLastExpected.add(1618969016L);
+            firstAndLastExpected.add(35213705L);
+            assertEquals(firstAndLastExpected, firstAndLastObtained);
+        }
+    }
+}