Add tests for merging duplicate ways, with some fixes

Signed-off-by: Taylor Smock <taylor.smock@kaart.com>

src/main/java/org/openstreetmap/josm/plugins/mapwithai/backend/MergeDuplicateWaysAction.java

@@ -36,22 +36,28 @@ public class MergeDuplicateWaysAction extends JosmAction {
 
     @Override
     public void actionPerformed(ActionEvent e) {
-        final List<Way> ways = new ArrayList<>(MainApplication.getLayerManager().getActiveDataSet().getSelectedWays());
-        Command command = null;
-        int i = 0;
-        do {
-            if (ways.size() == 2) {
-                command = new MergeDuplicateWays(ways.get(0), ways.get(1));
-            } else if (ways.size() == 1) {
-                command = new MergeDuplicateWays(ways.get(0));
-            } else if (ways.isEmpty()) {
-                command = new MergeDuplicateWays(MainApplication.getLayerManager().getActiveDataSet());
-            }
-            if (command != null) {
-                UndoRedoHandler.getInstance().add(command);
-                i++;
-            }
-        } while (command != null && i < 1);
+        if (MainApplication.getLayerManager().getActiveDataSet() != null) {
+            final List<Way> ways = new ArrayList<>(MainApplication.getLayerManager().getActiveDataSet().getSelectedWays());
+            Command command = null;
+            int i = 0;
+            do {
+                if (ways.size() == 2) {
+                    command = new MergeDuplicateWays(ways.get(0), ways.get(1));
+                } else if (ways.size() == 1) {
+                    command = new MergeDuplicateWays(ways.get(0));
+                } else if (ways.isEmpty()) {
+                    command = new MergeDuplicateWays(MainApplication.getLayerManager().getActiveDataSet());
+                }
+                if (command != null) {
+                    UndoRedoHandler.getInstance().add(command);
+                    i++;
+                }
+            } while (command != null && i < 1);
+        }
     }
 
+    @Override
+    public void updateEnabledState() {
+        setEnabled(MainApplication.getLayerManager().getActiveDataSet() != null);
+    }
 }

test/unit/org/openstreetmap/josm/plugins/mapwithai/backend/MergeDuplicateWaysActionTest.java

@@ -0,0 +1,82 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.plugins.mapwithai.backend;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Arrays;
+import java.util.Collections;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.openstreetmap.josm.TestUtils;
+import org.openstreetmap.josm.data.UndoRedoHandler;
+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.gui.MainApplication;
+import org.openstreetmap.josm.gui.layer.OsmDataLayer;
+import org.openstreetmap.josm.testutils.JOSMTestRules;
+
+/**
+ * @author Taylor Smock
+ */
+public class MergeDuplicateWaysActionTest {
+    @Rule
+    public JOSMTestRules rules = new JOSMTestRules().preferences().projection().main();
+
+    MergeDuplicateWaysAction action;
+
+    @Before
+    public void setUp() {
+        action = new MergeDuplicateWaysAction();
+    }
+
+    @Test
+    public void testActionPerformed() {
+        action.actionPerformed(null);
+        MainApplication.getLayerManager().addLayer(new OsmDataLayer(new DataSet(), "Test Layer", null));
+        DataSet ds = MainApplication.getLayerManager().getActiveDataSet();
+        action.actionPerformed(null);
+        UndoRedoHandler.getInstance().undo();
+
+        Way way1 = TestUtils.newWay("", new Node(new LatLon(0, 0)), new Node(new LatLon(0, 1)));
+        Way way2 = TestUtils.newWay("", new Node(new LatLon(0, 0)), new Node(new LatLon(0, 1)));
+        Way way3 = TestUtils.newWay("", new Node(new LatLon(1, 1)), new Node(new LatLon(2, 1)));
+        for (Way way : Arrays.asList(way1, way2, way3)) {
+            way.getNodes().forEach(ds::addPrimitive);
+            ds.addPrimitive(way);
+        }
+
+        runCommand(way1, way2);
+
+        ds.setSelected(way1);
+        runCommand(way1, way2);
+
+        ds.addSelected(Collections.singleton(way2));
+        runCommand(way1, way2);
+
+        ds.addSelected(Collections.singleton(way3));
+        action.actionPerformed(null);
+        assertFalse(UndoRedoHandler.getInstance().hasUndoCommands());
+    }
+
+    private void runCommand(Way way1, Way way2) {
+        action.actionPerformed(null);
+        assertNotEquals(way1.isDeleted(), way2.isDeleted());
+        UndoRedoHandler.getInstance().undo();
+        assertEquals(way1.isDeleted(), way2.isDeleted());
+        assertFalse(way1.isDeleted());
+    }
+
+    @Test
+    public void testUpdateEnabledState() {
+        assertFalse(action.isEnabled());
+        MainApplication.getLayerManager().addLayer(new OsmDataLayer(new DataSet(), "Test Layer", null));
+        assertTrue(action.isEnabled());
+    }
+}