diff --git a/affinity/src/test/java/net/openhft/affinity/LockCheckTest.java b/affinity/src/test/java/net/openhft/affinity/LockCheckTest.java
index 40f5d18e5..2612886ce 100644
--- a/affinity/src/test/java/net/openhft/affinity/LockCheckTest.java
+++ b/affinity/src/test/java/net/openhft/affinity/LockCheckTest.java
@@ -55,6 +55,11 @@ public void testPidOnLinux() {
         Assert.assertTrue(LockCheck.isProcessRunning(LockCheck.getPID()));
     }
 
+    @Test
+    public void testNegativePidOnLinux() {
+        Assert.assertFalse(LockCheck.isProcessRunning(-1));
+    }
+
     @Test
     public void testReplace() throws IOException {
         cpu++;