Add a test suite

README.md

@@ -11,5 +11,15 @@ There's an example of a "fake login" program in the examples directory.
 Look at the pam module's [godocs][1] for details about the Go API, or refer
 to the official [PAM documentation][2].
 
+The test suite must be run as the root user. To setup your system for testing,
+create a user named "test" with the password "secret". For example:
+
+```
+$ sudo useradd test \
+    -d /tmp/test \
+    -p '$1$Qd8H95T5$RYSZQeoFbEB.gS19zS99A0' \
+    -s /bin/false
+```
+
 [1]: http://godoc.org/github.com/msteinert/pam
 [2]: http://www.kernel.org/pub/linux/libs/pam/Linux-PAM-html/adg-interface-by-app-expected.html