Clean up timeout and add tests.

lib/fog/core/timeout.rb

@@ -1,13 +1,10 @@
 module Fog
+  def self.timeout
+    @timeout ||= 600
+  end
 
-    @timeout = 600
-    def self.timeout
-      @timeout
-    end
-
-    def self.timeout=(new_timeout)
-      raise ArgumentError, "timeout must be non-negative" unless new_timeout >= 0
-      @timeout = new_timeout
-    end
-
+  def self.timeout=(timeout)
+    raise ArgumentError, "timeout must be non-negative" unless timeout >= 0
+    @timeout = timeout
+  end
 end

tests/core/timeout_tests.rb

@@ -0,0 +1,10 @@
+Shindo.tests('Fog#timeout', 'core') do
+  tests('timeout').returns(600) do
+    Fog.timeout
+  end
+
+  tests('timeout = 300').returns(300) do
+    Fog.timeout = 300
+    Fog.timeout
+  end
+end