Added document about testing and profiling

TESTING.md

@@ -0,0 +1,70 @@
+# Testing and Profiling
+
+This is a short document to help out anyone who wants to
+contribute to development of Sonic Pi. To do that you should
+try to use (and add to) the test suites.
+
+## Running the tests
+
+Sonic Pi doesn't have a database, so the tests are quite a lot
+simpler than your average web app.
+
+```
+$ cd app/server/sonicpi/test
+$ rake test
+```
+
+This should run all the tests for you. 
+
+If you have an error like this:
+
+```
+Warning: you should require 'minitest/autorun' instead.
+Warning: or add 'gem "minitest"' before 'require "minitest/autorun"'
+```
+
+You may find you need to run the following.
+
+```
+$ gem install test-unit
+```
+
+## Profiling
+
+Sonic Pi is a truly multi-threaded system with communications via OSC
+(open sound control) being sent between the Qt GUI, the Ruby server and
+the scsynth synthesis server. As a result, profiling has proved to be tricky.
+
+### Profiling the Ruby server
+
+The following is a suggestion for how one might go about profiling the Ruby
+elements of Sonic Pi. This assumes you are using Ruby 2.1 or greater.
+
+1. `gem install ruby-prof`
+2. (optional) Clone [this repo](https://github.com/xavriley/tinyosc), run `build.sh` followed by `./tinyosc 4557`
+ This is just to provide a receiver for the OSC message that are sent to the GUI
+on port 4557. If you don't do this you'll see some error messages to do with connections.
+3. `gem install sonic-pi-cli` - for version 2.7 dev and above you may need to install from this repo: https://github.com/xavriley/sonic-pi-cli
+4. Run this command from the root dir of Sonic Pi
+
+```
+$ ruby-prof -p multi ./app/server/bin/sonic-pi-server.rb
+```
+
+5. Run this command (again from the root dir) to send some code to Sonic Pi
+
+```
+$ cat etc/examples/wizard/tilburg.rb | sonic_pi
+```
+
+6. After letting it run for a while, run `sonic_pi stop` in a fresh terminal
+and then Ctrl+C the sonic-pi-server.rb process. This should create several
+files in the root folder containing profiling information.
+
+### Profiling the Qt GUI
+
+TODO
+
+### Profiling `scsynth`
+
+TODO