Users can update their existing bourbon installation.

.gitignore

@@ -4,3 +4,4 @@
 bourbon/
 demo/
 tmp/
+tags

bin/bourbon

@@ -2,4 +2,4 @@
 
 require "bourbon"
 
-Bourbon::Generator.new.generate
+Bourbon::Generator.new(ARGV).run

features/generate.feature

@@ -1,8 +1,7 @@
 @disable-bundler
-Feature: Generate bourbon files via gem subcommand
+Feature: Generate bourbon files
 
   Scenario: Run `bourbon generate`
-    Given I set up bourbon
     When I generate bourbon files
     Then the sass directories should have been generated
     And the following directories should exist:

features/step_definitions/bourbon_steps.rb

@@ -3,12 +3,13 @@
   generate_bourbon
 end
 
-When /^I set up bourbon$/ do
+When /^I generate bourbon files$/ do
   set_up_bourbon_directory
+  generate_bourbon
 end
 
-When /^I generate bourbon files$/ do
-  generate_bourbon
+When /^I update bourbon files$/ do
+  update_bourbon
 end
 
 Then /^the sass directories should have been generated$/ do
@@ -24,3 +25,7 @@
   check_file_presence(["bourbon/lib/sass_extensions.rb"], true)
   check_directory_presence(["bourbon/lib/sass_extensions"], true)
 end
+
+Then /^bourbon should not have been generated$/ do
+  check_directory_presence(["bourbon"], false)
+end

features/support/bourbon_support.rb

@@ -7,6 +7,10 @@ def set_up_bourbon_directory
   def generate_bourbon
     run_simple("bundle exec bourbon generate")
   end
+
+  def update_bourbon
+    run_simple("bundle exec bourbon update")
+  end
 end
 
 World(BourbonSupport)

features/update.feature

@@ -0,0 +1,17 @@
+@disable-bundler
+Feature: Update bourbon files
+
+  Scenario: `bourbon update` updates an existing bourbon install
+    When I generate bourbon files
+    And I write to "bourbon/_bourbon.scss" with:
+      """
+      foobar
+      """
+    And I update bourbon files
+    Then the output should contain "Bourbon files updated."
+    And the file "bourbon/_bourbon.scss" should not contain "foobar"
+
+  Scenario: `bourbon update` does not generate a new bourbon install
+    When I update bourbon files
+    Then bourbon should not have been generated
+    And the output should contain "No existing bourbon installation. Doing nothing."