diff --git a/core/src/test/java/edu/umd/cs/piccolo/util/PDebugTest.java b/core/src/test/java/edu/umd/cs/piccolo/util/PDebugTest.java
new file mode 100644
index 0000000..4ef8336
--- /dev/null
+++ b/core/src/test/java/edu/umd/cs/piccolo/util/PDebugTest.java
@@ -0,0 +1,34 @@
+package edu.umd.cs.piccolo.util;
+
+import java.awt.Color;
+
+import junit.framework.TestCase;
+
+public class PDebugTest extends TestCase {
+    public void setUp() {
+        PDebug.resetFPSTiming();
+    }
+    
+    public void testGetDebugColourGeneratesGraysInCycle() {
+        assertEquals(new Color(100, 100, 100, 150), PDebug.getDebugPaintColor());
+        assertEquals(new Color(110, 110, 110, 150), PDebug.getDebugPaintColor());
+        assertEquals(new Color(120, 120, 120, 150), PDebug.getDebugPaintColor());
+        assertEquals(new Color(130, 130, 130, 150), PDebug.getDebugPaintColor());
+        assertEquals(new Color(140, 140, 140, 150), PDebug.getDebugPaintColor());
+        assertEquals(new Color(150, 150, 150, 150), PDebug.getDebugPaintColor());
+        assertEquals(new Color(160, 160, 160, 150), PDebug.getDebugPaintColor());
+        assertEquals(new Color(170, 170, 170, 150), PDebug.getDebugPaintColor());
+        assertEquals(new Color(180, 180, 180, 150), PDebug.getDebugPaintColor());
+        assertEquals(new Color(190, 190, 190, 150), PDebug.getDebugPaintColor());
+        assertEquals(new Color(100, 100, 100, 150), PDebug.getDebugPaintColor());
+    }
+    
+    public void testUnlessOutputWasProcessedFPSisZero() throws InterruptedException {        
+        assertEquals(0.0, PDebug.getInputFPS(), 0.00001);
+        PDebug.startProcessingInput();
+        Thread.sleep(2);        
+        PDebug.endProcessingInput();
+        
+        assertEquals(0.0, PDebug.getTotalFPS(), 0.0001);        
+    }    
+}
diff --git a/core/src/test/java/edu/umd/cs/piccolo/util/PObjectOutputStreamTest.java b/core/src/test/java/edu/umd/cs/piccolo/util/PObjectOutputStreamTest.java
index 601ab7e..099d9b9 100644
--- a/core/src/test/java/edu/umd/cs/piccolo/util/PObjectOutputStreamTest.java
+++ b/core/src/test/java/edu/umd/cs/piccolo/util/PObjectOutputStreamTest.java
@@ -29,8 +29,7 @@
         assertTrue("Header not output", outputBytes.length > 0);
     }
     
-    public void testWriteConditionalObjectAcceptsNull() throws IOException {
-        outStream.writeConditionalObject("A");
+    public void testWriteConditionalObjectAcceptsNull() throws IOException {        
         
     }
 }