diff --git a/doc/en/customize.txt b/doc/en/customize.txt
index d436a0672..99fd8ffc8 100644
--- a/doc/en/customize.txt
+++ b/doc/en/customize.txt
@@ -121,6 +121,8 @@ Builtin configuration file options
 .. confval:: python_functions
 
    One or more name prefixes determining which test functions
-   and methods are considered as test modules.
+   and methods are considered as test modules.  Note that this
+   has no effect on methods that live on a ``unittest.TestCase`` 
+   derived class.
 
    See :ref:`change naming conventions` for examples.
diff --git a/doc/en/example/pythoncollection.txt b/doc/en/example/pythoncollection.txt
index abf6340c0..311140c91 100644
--- a/doc/en/example/pythoncollection.txt
+++ b/doc/en/example/pythoncollection.txt
@@ -53,6 +53,12 @@ then the test collection looks like this::
     
     =============================  in 0.01 seconds =============================
 
+.. note::
+   
+   the ``python_functions`` and ``python_classes`` has no effect
+   for ``unittest.TestCase`` test discovery because pytest delegates
+   detection of test case methods to unittest code.
+
 Interpreting cmdline arguments as Python packages
 -----------------------------------------------------