diff --git a/extras/src/main/java/edu/umd/cs/piccolox/pswing/PSwingEventHandler.java b/extras/src/main/java/edu/umd/cs/piccolox/pswing/PSwingEventHandler.java
index 464c244..b79490b 100644
--- a/extras/src/main/java/edu/umd/cs/piccolox/pswing/PSwingEventHandler.java
+++ b/extras/src/main/java/edu/umd/cs/piccolox/pswing/PSwingEventHandler.java
@@ -114,7 +114,7 @@
     /**
      * Sets whether this event handler can fire events.
      * 
-     * @param active true if thie event handler can fire events
+     * @param active true if this event handler can fire events
      */
     void setActive(final boolean active) {
         if (this.active && !active) {
@@ -266,11 +266,11 @@
         }
         else if (isWheelEvent(pSwingMouseEvent) && comp != null) {
             final MouseWheelEvent mWEvent = (MouseWheelEvent) mEvent;
-            
+
             final MouseWheelEvent tempEvent = new MouseWheelEvent(comp, pSwingMouseEvent.getID(), mEvent.getWhen(),
                     mEvent.getModifiers(), point.x - offset.x, point.y - offset.y, mEvent.getClickCount(), mEvent
-                            .isPopupTrigger(), mWEvent.getScrollType(), mWEvent.getScrollAmount(), mWEvent
-                            .getWheelRotation());
+                    .isPopupTrigger(), mWEvent.getScrollType(), mWEvent.getScrollAmount(), mWEvent
+                    .getWheelRotation());
 
             final PSwingMouseWheelEvent e2 = new PSwingMouseWheelEvent(tempEvent.getID(), tempEvent, aEvent);
             dispatchEvent(comp, e2);
@@ -465,29 +465,34 @@
      * Process a Piccolo2D event and (if active) dispatch the corresponding
      * Swing event.
      * 
-     * @param aEvent Piccolo2D event being testing for dispatch to swing
+     * @param aEvent Piccolo2D event being tested for dispatch to swing
      * @param type is not used in this method
      */
     public void processEvent(final PInputEvent aEvent, final int type) {
-        if (aEvent.isMouseEvent()) {
-            final InputEvent sourceSwingEvent = aEvent.getSourceSwingEvent();
-            if (sourceSwingEvent instanceof MouseEvent) {
-                final MouseEvent swingMouseEvent = (MouseEvent) sourceSwingEvent;
-                final PSwingEvent pSwingMouseEvent = PSwingMouseEvent.createMouseEvent(swingMouseEvent.getID(),
-                        swingMouseEvent, aEvent);
-                if (!recursing) {
-                    recursing = true;
-                    dispatchEvent(pSwingMouseEvent, aEvent);
-                    if (pSwingMouseEvent.asMouseEvent().isConsumed()) {
-                        aEvent.setHandled(true);
-                    }
-                    recursing = false;
-                }
+        if (!aEvent.isMouseEvent()) {
+            return;
+        }
+
+        final InputEvent sourceSwingEvent = aEvent.getSourceSwingEvent();
+        if (!(sourceSwingEvent instanceof MouseEvent)) {
+            throw new RuntimeException("PInputEvent.getSourceSwingEvent was not a MouseEvent.  Actual event: "
+                    + sourceSwingEvent + ", class=" + sourceSwingEvent.getClass().getName());
+        }
+
+        processMouseEvent(aEvent, (MouseEvent) sourceSwingEvent);
+    }
+
+    private void processMouseEvent(final PInputEvent aEvent, final MouseEvent swingMouseEvent) {
+        if (!recursing) {
+            recursing = true;
+            final PSwingEvent pSwingMouseEvent = PSwingMouseEvent.createMouseEvent(swingMouseEvent.getID(),
+                    swingMouseEvent, aEvent);
+            
+            dispatchEvent(pSwingMouseEvent, aEvent);
+            if (pSwingMouseEvent.asMouseEvent().isConsumed()) {
+                aEvent.setHandled(true);
             }
-            else {
-                throw new RuntimeException("PInputEvent.getSourceSwingEvent was not a MouseEvent.  Actual event: "
-                        + sourceSwingEvent + ", class=" + sourceSwingEvent.getClass().getName());
-            }
+            recursing = false;
         }
     }
 
diff --git a/extras/src/main/java/edu/umd/cs/piccolox/pswing/PSwingMouseEvent.java b/extras/src/main/java/edu/umd/cs/piccolox/pswing/PSwingMouseEvent.java
index 7197cfc..fc91f3c 100644
--- a/extras/src/main/java/edu/umd/cs/piccolox/pswing/PSwingMouseEvent.java
+++ b/extras/src/main/java/edu/umd/cs/piccolox/pswing/PSwingMouseEvent.java
@@ -109,6 +109,10 @@
      * @return the constructed PSwingEvent
      */
     public static PSwingEvent createMouseEvent(final int id, final MouseEvent swingEvent, final PInputEvent pEvent) {
+        if (pEvent == null) {
+            throw new IllegalArgumentException("PInputEvent associated with PSwingEvent may not be null");
+        }
+        
         if (id == MouseEvent.MOUSE_MOVED || id == MouseEvent.MOUSE_DRAGGED) {
             return new PSwingMouseMotionEvent(id, swingEvent, pEvent);
         }
diff --git a/extras/src/test/java/edu/umd/cs/piccolox/pswing/PSwingEventHandlerTest.java b/extras/src/test/java/edu/umd/cs/piccolox/pswing/PSwingEventHandlerTest.java
new file mode 100644
index 0000000..4431582
--- /dev/null
+++ b/extras/src/test/java/edu/umd/cs/piccolox/pswing/PSwingEventHandlerTest.java
@@ -0,0 +1,11 @@
+package edu.umd.cs.piccolox.pswing;
+
+import junit.framework.TestCase;
+
+public class PSwingEventHandlerTest extends TestCase {
+
+    public void testConstructorAcceptsNullTargetNode() {
+        PSwingCanvas canvas = new PSwingCanvas();
+        PSwingEventHandler handler = new PSwingEventHandler(canvas, null);
+    }
+}
diff --git a/extras/src/test/java/edu/umd/cs/piccolox/pswing/PSwingMouseEventTest.java b/extras/src/test/java/edu/umd/cs/piccolox/pswing/PSwingMouseEventTest.java
new file mode 100644
index 0000000..0f2f4e7
--- /dev/null
+++ b/extras/src/test/java/edu/umd/cs/piccolox/pswing/PSwingMouseEventTest.java
@@ -0,0 +1,74 @@
+package edu.umd.cs.piccolox.pswing;
+
+import java.awt.event.MouseEvent;
+import java.awt.event.MouseWheelEvent;
+
+import javax.swing.JComponent;
+import javax.swing.JPanel;
+
+import junit.framework.TestCase;
+import edu.umd.cs.piccolo.event.PInputEvent;
+
+public class PSwingMouseEventTest extends TestCase {
+
+    public void testCreateMouseEventDoesNotAcceptNullPInputEvent() {
+        try {
+            MouseEvent mouseEvent = new MouseEvent(null, MouseEvent.MOUSE_MOVED, System.currentTimeMillis(), 0, 0, 0,
+                    0, false);
+            PSwingMouseEvent.createMouseEvent(0, mouseEvent, null);
+            fail("Null PInputEvent should throw an exception");
+        }
+        catch (IllegalArgumentException iae) {
+            // expected exception
+        }
+    }
+
+    public void testCreateMouseEventDoesNotAcceptNullMouseEvent() {
+        try {
+            PInputEvent event = new PInputEvent(null, null);
+            PSwingMouseEvent.createMouseEvent(0, null, event);
+            fail("Null MouseEvent should throw an exception");
+        }
+        catch (NullPointerException iae) {
+            // expected exception
+        }
+    }
+
+    public void testCreateMouseEventReturnsValidMouseEventWhenParamsAreGood() {
+        JComponent src = new JPanel();
+        PInputEvent piccoloEvent = new PInputEvent(null, null);
+        MouseEvent mouseEvent = new MouseEvent(src, MouseEvent.MOUSE_MOVED, System.currentTimeMillis(), 0, 0, 0, 0,
+                false);
+        PSwingEvent swingEvent = PSwingMouseEvent.createMouseEvent(0, mouseEvent, piccoloEvent);
+        assertNotNull(swingEvent);
+    }
+
+    public void testCreateMouseEventReturnsPSwingMouseEventWhenGivenGenericID() {
+        JComponent src = new JPanel();
+        PInputEvent piccoloEvent = new PInputEvent(null, null);
+        MouseEvent mouseEvent = new MouseEvent(src, 0, System.currentTimeMillis(), 0, 0, 0, 0,
+                false);
+        PSwingEvent swingEvent = PSwingMouseEvent.createMouseEvent(0, mouseEvent, piccoloEvent);
+        assertTrue(swingEvent instanceof PSwingMouseEvent);
+    }
+
+    public void testCreateMouseEventReturnsPSwingMouseMotionEventWhenGivenMotionID() {
+        JComponent src = new JPanel();
+        PInputEvent piccoloEvent = new PInputEvent(null, null);
+        MouseEvent mouseEvent = new MouseEvent(src, MouseEvent.MOUSE_MOVED, System.currentTimeMillis(), 0, 0, 0, 0,
+                false);
+        PSwingEvent swingEvent = PSwingMouseEvent.createMouseEvent(MouseEvent.MOUSE_MOVED, mouseEvent, piccoloEvent);
+        assertTrue(swingEvent instanceof PSwingMouseMotionEvent);
+    }
+
+    public void testCreateMouseEventReturnsPSwingMouseWheelEventWhenGivenWheelID() {
+        JComponent src = new JPanel();
+        PInputEvent piccoloEvent = new PInputEvent(null, null);
+        MouseWheelEvent mouseEvent = new MouseWheelEvent(src, MouseEvent.MOUSE_WHEEL, System.currentTimeMillis(), 0, 0,
+                0, 0,
+                false, MouseWheelEvent.WHEEL_UNIT_SCROLL, 10, 1);
+        PSwingEvent swingEvent = PSwingMouseEvent.createMouseEvent(MouseEvent.MOUSE_WHEEL, mouseEvent, piccoloEvent);
+        assertTrue(swingEvent instanceof PSwingMouseWheelEvent);
+    }
+
+}