Index: applications/editors/josm/plugins/mapillary/test/unit/org/openstreetmap/josm/plugins/mapillary/history/MapillaryRecordTest.java
===================================================================
--- applications/editors/josm/plugins/mapillary/test/unit/org/openstreetmap/josm/plugins/mapillary/history/MapillaryRecordTest.java	(revision 32653)
+++ applications/editors/josm/plugins/mapillary/test/unit/org/openstreetmap/josm/plugins/mapillary/history/MapillaryRecordTest.java	(revision 32659)
@@ -177,6 +177,6 @@
   @Test
   public void commandJoinClass() {
-    CommandJoin cmd1 = new CommandJoin(Arrays.asList(new MapillaryAbstractImage[]{img1, img2}));
-    CommandJoin cmd2 = new CommandJoin(Arrays.asList(new MapillaryAbstractImage[]{img2, img3}));
+    CommandJoin cmd1 = new CommandJoin(img1, img2);
+    CommandJoin cmd2 = new CommandJoin(img2, img3);
 
     this.record.addCommand(cmd1);
@@ -189,11 +189,14 @@
     assertEquals(3, img1.getSequence().getImages().size());
     assertEquals(img3, img1.next().next());
-
-    try {
-      this.record.addCommand(new CommandJoin(Arrays.asList(new MapillaryAbstractImage[]{img1, img2, img3})));
-      fail();
-    } catch (IllegalArgumentException e) {
-      // Expected output.
-    }
+  }
+  
+  @Test(expected=NullPointerException.class)
+  public void commandJoinNull1() {
+    new CommandJoin(img1, null);
+  }
+  
+  @Test(expected=NullPointerException.class)
+  public void commandJoinNull2() {
+    new CommandJoin(null, img1);
   }
 
@@ -203,8 +206,6 @@
   @Test
   public void commandUnjoinClass() {
-    CommandJoin join1 = new CommandJoin(
-            Arrays.asList(new MapillaryAbstractImage[]{this.img1, this.img2}));
-    CommandJoin join2 = new CommandJoin(
-            Arrays.asList(new MapillaryAbstractImage[]{this.img2, this.img3}));
+    CommandJoin join1 = new CommandJoin(this.img1, this.img2);
+    CommandJoin join2 = new CommandJoin(this.img2, this.img3);
 
     CommandUnjoin cmd1 = new CommandUnjoin(
@@ -238,6 +239,6 @@
   @Test
   public void commandDeleteTest() {
-    CommandJoin join1 = new CommandJoin(Arrays.asList(new MapillaryAbstractImage[]{img1, img2}));
-    CommandJoin join2 = new CommandJoin(Arrays.asList(new MapillaryAbstractImage[]{img2, img3}));
+    CommandJoin join1 = new CommandJoin(img1, img2);
+    CommandJoin join2 = new CommandJoin(img2, img3);
 
     CommandDelete cmd1 = new CommandDelete(