Add testing instructions to README

README.md

@@ -14,7 +14,7 @@ Predoc uses [LibreOffice](http://www.libreoffice.org/) (via [Docsplit](http://do
 
 ### Configuration
 
-You need to specify the paths for Predoc to create temporary and cache files. Create `predoc.rb` from the template file `config/initializers/predoc.rb.default` in the same location, and modify these variables:
+You need to specify the paths for Predoc to create temporary and cache files. Create `predoc.rb` from the template file `config/initializers/predoc.rb.default` at the same location, and modify these variables:
 
 * `WORKING_DIRECTORY` is where temporary files are downloaded and stored.
 * `CACHE_ROOT_DIRECTORY` is where converted files are cached.
@@ -29,3 +29,10 @@ To create a preview, point your web browser to the web service:
     http://example.com/viewer?url=http://path/to/document
 
 *Note: Replace `example.com` with the server hostname, and `http://path/to/document` with an actual web-hosted document*
+
+Testing
+-------
+
+To run unit tests, first create `test.rb` from the template file `config/test.rb.default` at the same location. Change the URL values in `FIXTURE_URLS` to real web-hosted test documents (not provided). Run this command to start the test:
+
+    ruby -Itest test/functional/documents_controller_test.rb