Index: trunk/test/unit/org/openstreetmap/josm/actions/JoinNodeWayActionTest.java
===================================================================
--- trunk/test/unit/org/openstreetmap/josm/actions/JoinNodeWayActionTest.java	(revision 15428)
+++ trunk/test/unit/org/openstreetmap/josm/actions/JoinNodeWayActionTest.java	(revision 15428)
@@ -0,0 +1,181 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.actions;
+
+import static org.junit.Assert.assertTrue;
+
+import java.awt.Rectangle;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.openstreetmap.josm.TestUtils;
+import org.openstreetmap.josm.data.coor.EastNorth;
+import org.openstreetmap.josm.data.coor.LatLon;
+import org.openstreetmap.josm.data.osm.DataSet;
+import org.openstreetmap.josm.data.osm.Node;
+import org.openstreetmap.josm.data.osm.Way;
+import org.openstreetmap.josm.data.osm.visitor.BoundingXYVisitor;
+import org.openstreetmap.josm.gui.MainApplication;
+import org.openstreetmap.josm.gui.layer.Layer;
+import org.openstreetmap.josm.gui.layer.OsmDataLayer;
+import org.openstreetmap.josm.io.OsmReader;
+import org.openstreetmap.josm.testutils.JOSMTestRules;
+import org.openstreetmap.josm.tools.Geometry;
+
+import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
+
+/**
+ * Unit tests for class {@link JoinNodeWayAction}.
+ */
+public final class JoinNodeWayActionTest {
+    /**
+     * Setup test.
+     */
+    @Rule
+    @SuppressFBWarnings(value = "URF_UNREAD_PUBLIC_OR_PROTECTED_FIELD")
+    public JOSMTestRules test = new JOSMTestRules().projection().main().preferences();
+
+    private void setupMapView(DataSet ds) {
+        // setup a reasonable screen size
+        MainApplication.getMap().mapView.setBounds(new Rectangle(1920, 1080));
+        if (ds.getDataSourceBoundingBox() != null) {
+            MainApplication.getMap().mapView.zoomTo(ds.getDataSourceBoundingBox());
+        } else {
+            BoundingXYVisitor v = new BoundingXYVisitor();
+            for (Layer l : MainApplication.getLayerManager().getLayers()) {
+                l.visitBoundingBox(v);
+            }
+            MainApplication.getMap().mapView.zoomTo(v);
+        }
+    }
+
+    /**
+     * Test case: Move node onto two almost overlapping ways
+     * see #18189 moveontoway.osm
+     * @throws Exception if an error occurs
+     */
+    @Test
+    public void testTicket18189() throws Exception {
+        DataSet dataSet = new DataSet();
+        OsmDataLayer layer = new OsmDataLayer(dataSet, OsmDataLayer.createNewName(), null);
+        MainApplication.getLayerManager().addLayer(layer);
+        try {
+            Node n1 = new Node(new LatLon(59.92881498658, 30.30104052971));
+            Node n2 = new Node(new LatLon(59.92881459851, 30.30104056556));
+            Node n3 = new Node(new LatLon(59.92881498658, 30.3010405297));
+            Node n4 = new Node(new LatLon(59.92881459851, 30.30104056556));
+            Node n5 = new Node(new LatLon(59.92881483122, 30.30104056465));
+
+            dataSet.addPrimitive(n1);
+            dataSet.addPrimitive(n2);
+            dataSet.addPrimitive(n3);
+            dataSet.addPrimitive(n4);
+            dataSet.addPrimitive(n5);
+
+            Way w1 = new Way();
+            w1.setNodes(Arrays.asList(n1, n2));
+            dataSet.addPrimitive(w1);
+            Way w2 = new Way();
+            w2.setNodes(Arrays.asList(n3, n4));
+            dataSet.addPrimitive(w2);
+
+            dataSet.addSelected(n5);
+            EastNorth expected = Geometry.closestPointToSegment(n1.getEastNorth(), n2.getEastNorth(), n5.getEastNorth());
+
+            setupMapView(dataSet);
+            JoinNodeWayAction action = JoinNodeWayAction.createMoveNodeOntoWayAction();
+            action.setEnabled(true);
+            action.actionPerformed(null);
+            // Make sure the node was only moved once
+            assertTrue("Node n5 wasn't added to way w1.", w1.containsNode(n5));
+            assertTrue("Node n5 wasn't added to way w2.", w2.containsNode(n5));
+            assertTrue("Node was moved to an unexpected position", n5.getEastNorth().equalsEpsilon(expected, 1e-7));
+        } finally {
+            MainApplication.getLayerManager().removeLayer(layer);
+        }
+    }
+
+    /**
+     * Non-regression test for <a href="https://josm.openstreetmap.de/ticket/11508">Bug #11508</a>.
+     * @throws Exception if an error occurs
+     */
+    @Test
+    public void testTicket11508() throws Exception {
+        DataSet ds = OsmReader.parseDataSet(TestUtils.getRegressionDataStream(11508, "11508_example.osm"), null);
+        Layer layer = new OsmDataLayer(ds, OsmDataLayer.createNewName(), null);
+        MainApplication.getLayerManager().addLayer(layer);
+        try {
+            List<Node> nodesToMove = ds.getNodes().stream().filter(n -> n.hasTag("name", "select me and press N"))
+                    .collect(Collectors.toList());
+            assertTrue(nodesToMove.size() == 1);
+            Node toMove = nodesToMove.iterator().next();
+            Node expected = new Node(new LatLon(47.56331849690742, 8.800789259499311));
+            ds.setSelected(toMove);
+            setupMapView(ds);
+            JoinNodeWayAction action = JoinNodeWayAction.createMoveNodeOntoWayAction();
+            action.setEnabled(true);
+            action.actionPerformed(null);
+
+            assertTrue("Node was moved to an unexpected position", toMove.getEastNorth().equalsEpsilon(expected.getEastNorth(), 1e-7));
+            assertTrue("Node was not added to expected number of ways", toMove.getParentWays().size() == 2);
+        } finally {
+            MainApplication.getLayerManager().removeLayer(layer);
+        }
+    }
+
+    /**
+     * Check that nothing is changed if ways are too far.
+     * @throws Exception if an error occurs
+     */
+    @Test
+    public void testTicket18189Crossing() throws Exception {
+        DataSet ds = OsmReader.parseDataSet(TestUtils.getRegressionDataStream(18189, "moveontocrossing.osm"), null);
+        Layer layer = new OsmDataLayer(ds, OsmDataLayer.createNewName(), null);
+        MainApplication.getLayerManager().addLayer(layer);
+        try {
+            setupMapView(ds);
+            JoinNodeWayAction action = JoinNodeWayAction.createMoveNodeOntoWayAction();
+            action.setEnabled(true);
+            List<Node> nodesToMove = ds.getNodes().stream().filter(n -> n.hasTag("name", "select me and press N"))
+                    .collect(Collectors.toList());
+            assertTrue(nodesToMove.size() == 1);
+            Node toMove = nodesToMove.iterator().next();
+            ds.setSelected(toMove);
+            action.actionPerformed(null);
+            assertTrue(toMove.getParentWays().isEmpty());
+        } finally {
+            MainApplication.getLayerManager().removeLayer(layer);
+        }
+    }
+
+    /**
+     * Check that nothing is changed if ways are too far.
+     * @throws Exception if an error occurs
+     */
+    @Test
+    public void testTicket18189ThreeWays() throws Exception {
+        DataSet ds = OsmReader.parseDataSet(TestUtils.getRegressionDataStream(18189, "data.osm"), null);
+        Layer layer = new OsmDataLayer(ds, OsmDataLayer.createNewName(), null);
+        MainApplication.getLayerManager().addLayer(layer);
+        try {
+            setupMapView(ds);
+            JoinNodeWayAction action = JoinNodeWayAction.createMoveNodeOntoWayAction();
+            action.setEnabled(true);
+            List<Node> nodesToMove = ds.getNodes().stream().filter(n -> n.hasTag("name", "select me and press N"))
+                    .collect(Collectors.toList());
+            assertTrue(nodesToMove.size() == 1);
+            Node toMove = nodesToMove.iterator().next();
+            Node expected = new Node(new LatLon(-21.088998104148224, -50.38629102179512));
+            ds.setSelected(toMove);
+            action.actionPerformed(null);
+            assertTrue("Node was moved to an unexpected position", toMove.getEastNorth().equalsEpsilon(expected.getEastNorth(), 1e-7));
+            assertTrue("Node was not added to expected number of ways", toMove.getParentWays().size() == 4);
+
+        } finally {
+            MainApplication.getLayerManager().removeLayer(layer);
+        }
+    }
+
+}