Configuring nose2

Configuration Files

nose2 can be configured via standard, ini-style config files. The default files are unittest.cfg and nose2.cfg in the start directory.

The ini format has sections marked off by brackets (”[unittest]”) and key = value pairs within those sections. When the value is a list, put each value into its own line with proper indentation

key_expecting_list = value1

Two command line options, -c and --no-user-config may be used to determine which config files are loaded.

-c CONFIG, --config CONFIG

Config files to load. Default behavior is to look for unittest.cfg and nose2.cfg in the start directory, as well as any user config files (unless --no-user-config is selected).


Do not load user config files. If not specified, in addition to the standard config files and any specified with -c, nose2 will look for .unittest.cfg and .nose2.cfg in the user’s $HOME directory.

Configuring Test Discovery

The [unittest] section of nose2 config files is used to configure nose2 itself. The following options are available to configure test discovery:


This option configures the default directory to start discovery. The default value is "." (the current directory where nose2 is executed). This directory is where nose2 will start looking for tests.


This option configures nose2 to add the named directories to sys.path and the discovery path. Use this if your project has code in a location other than the top level of the project, or the directories lib or src. The value here may be a list: put each directory on its own line in the config file.


This option configures how nose detects test modules. It is a file glob.


This option configures how nose detects test functions and methods. The prefix set here will be matched (via simple string matching) against the start of the name of each method in test cases and each function in test modules.


start-dir = tests
code-directories = source
test-file-pattern = *
test-method-prefix = t

Specifying Plugins to Load

To avoid loading any plugins, use the --no-plugins option. Beware, though: nose2 does all test discovery and loading via plugins, so unless you are patching in a custom test loader and runner, when run with --no-plugins, nose2 will do nothing.


Do not load any plugins. This kills the nose2.

To specify plugins to load beyond the builtin plugins automatically loaded, add a plugins entry under the [unittest] section in a config file.


List of plugins to load. Put one plugin module on each line.

To exclude some plugins that would otherwise be loaded, add an exclude-plugins entry under the [unittest] section in a config file.


List of plugins to exclude. Put one plugin module on each line.


It bears repeating that in both plugins and exclude-plugins entries, you specify the plugin module, not the plugin class. The module is specified by the (dot-separated) fully qualified name.


plugins = myproject.plugins.frobulate

exclude-plugins = nose2.plugins.loader.functions

Configuring Plugins

Most plugins specify a config file section that may be used to configure the plugin. If nothing else, any plugin that specifies a config file section can be set to automatically register by including always-on = True in its config:

always-on = True

Plugins may accept any number of other config values, which may be booleans, strings, integers or lists. A polite plugin will document these options somewhere. Plugins that want to make use of nose2’s Sphinx extension as detailed in Documenting plugins must extract all of their config values in their __init__ methods.

Test Runner Tips and Tweaks

Running Tests in a Single Module

You can use nose2.main in the same way that unittest.main (and unittest2.main) have historically worked: to run the tests in a single module. Just put a block like the following at the end of the module:

if __name__ == '__main__':
    import nose2

Then run the module directly – In other words, do not run the nose2 script.

Rolling Your Own Runner

You can take more control over the test runner by foregoing the nose2 script and rolling your own. To do that, you just need to write a script that calls, for instance:

if __name__ == '__main__':
  import nose2

You can pass several keyword arguments to, all of which are detailed in the documentation for nose2.main.PluggableTestProgram.

Altering the Default Plugin Set

To add plugin modules to the list of those automatically loaded, you can pass a list of module names to add (the plugins) argument or exclude (excludedPlugins). You can also subclass nose2.main.PluggableTestProgram and set the class-level defaultPlugins and excludePlugins attributes to alter plugin loading.

When Loading Plugins from Modules is not Enough

None of which will help if you need to register a plugin instance that you’ve loaded yourself. For that, use the extraHooks keyword argument to Here, you pass in a list of 2-tuples, each of which contains a hook name and a plugin instance to register for that hook. This allows you to register plugins that need runtime configuration that is not easily passed in through normal channels – and also to register objects that are not nose2 plugins as hook targets. Here’s a trivial example:

if __name__ == '__main__':
  import nose2

  class Hello(object):
      def startTestRun(self, event):
          print("hello!")[('startTestRun', Hello())])

This can come in handy when integrating with other systems that expect you to provide a test runner that they execute, rather than executing tests yourself (django, for instance).