If you're using Sinatra and you want to use rake to run your test suite, you will need to create a Rakefile and put this in it.

require 'rake/testtask'
task :default do
ENV['RACK_ENV'] = 'test'
Rake::Task['test'].invoke
end
Rake::TestTask.new(:default) do |t|
t.libs << "test"
t.pattern = 'test/*_test.rb'
t.verbose = true
end

This assumes your test suite is under the 'test/' directory and the files you want to test match the '_test.rb' pattern.

Now you can run rake from the command line and the default task (your test suite) will execute!

rake