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+title: NPTest
+parent: FAQ
+---
+
+# How do the NPTest parameters work?
+
+NPTest.pm is a perl module, originally written by Peter Bray, and provides
+some basic functions for testing the plugins.  It has two main helpers:
+`getTestParameter` and `testCmd`.
+
+## getTestParameter
+
+Used to get parameters given in previous test runs.  Use the 3 parameter
+version (the 4 parameter version is deprecated).
+
+Saved parameters are put in `/var/tmp/NPTest.cache`.  Unfortunately, there is
+no easy way of altering this - you will have to manually change this file to
+edit existing parameters.
+
+If you are adding new parameters, there are three values for the parameters
+that you need to be aware of:
+
+* default value
+* the value that you check against in the test script
+* an empty string, which is returned by getTestParameter when the test is run
+  via automated testing (technically, when no terminal is associated to the
+  test run)
+
+You should try and ensure current tests are not affected when a new parameter
+is added.  So it may be better to say `NP_INTERNET_ACCESS`, with information
+like *default "yes", disable with "no"* and check for
+`NP_INTERNET_ACCESS == "no"` to skip the tests.
+
+## testCmd
+
+This runs a command and returns an NPTest object back.  You can combine
+Test::More routines with the object to get the return code, output or perf
+data to test against expected values.
+
+See `plugins/t/check_disk.t` as an example test script.
+
+<!--% # vim:set filetype=markdown textwidth=78 joinspaces: # %-->