From 831eca50221accde729c3cb22c6d957f0b38804b Mon Sep 17 00:00:00 2001
From: Rowan Cockett <rowan@visiblegeology.com>
Date: Wed, 30 Oct 2013 23:28:14 -0600
Subject: [PATCH] Some documentation.

---
 SimPEG/tests/TestUtils.py | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/SimPEG/tests/TestUtils.py b/SimPEG/tests/TestUtils.py
index 83738a75..ff7ee668 100644
--- a/SimPEG/tests/TestUtils.py
+++ b/SimPEG/tests/TestUtils.py
@@ -192,6 +192,16 @@ def checkDerivative(fctn, x0, num=7, plotIt=True, dx=None):
         :rtype: bool
         :return: did you pass the test?!
 
+
+        .. plot::
+            :include-source:
+
+            from SimPEG.tests import checkDerivative
+            from SimPEG.utils import sdiag
+            import numpy as np
+            def simplePass(x):
+                return np.sin(x), sdiag(np.cos(x))
+            checkDerivative(simplePass, np.random.randn(5))
     """
 
     print "%s checkDerivative %s" % ('='*20, '='*20)