Understanding rake in order to keep on reading "Objects on Rails"

This document, I assume by Jim Weirich made me understand where rake came from and it will hopefully also make it easier for me to understand getting a grip on how it ticks. This is something I need when working with tools. I found the above in this rake tutorial.

Still I have a hard time finding a concise overview of what rake offers. Everyone talks about a DSL but I can only find bits and pieces of what this DSL offers. There seems no complete overview. Now in the above mentioned article I found that directory "tmp" creates a directory of the given name. Never seen this before.

Tasks are defined using the DSL like this task :name .... But for a task that execute tests I can only find this piece of code everywhere

Rake::TestTask.new do |t|
  t.libs << "test"
  t.test_files = FileList['test/test*.rb']
  t.verbose = true
end

should it not be something like this

task :test => [Rake::TestTask] do |t|
  t.libs << "test"
  t.test_files = FileList['test/test*.rb']
  t.verbose = true
end

I would understand that. But the very different syntax used above doesn't stick in my head and somehow yells at me "I don't want to be part of the DSL, I want to be Ruby".