Basic lifecycle support for installing preexisting files.

lib/basis/errors.rb

@@ -13,6 +13,12 @@ def initialize(directory)
     end
   end
 
+  class FileAlreadyExists < Reportable
+    def initialize(file)
+      super("#{file} already exists")
+    end
+  end
+
   class UnknownScheme < Reportable
     def initialize(url)
       super("Unknown URL scheme: #{url}")

lib/basis/installer.rb

@@ -8,14 +8,13 @@
 
 module Basis
   class Installer
-    attr_reader :source, :target
+    attr_reader :lifecycle, :source, :target
 
     def initialize(source, target)
       @source = Pathname.new(source).freeze
       @target = Pathname.new(target).freeze
 
       raise Basis::DirectoryNotFound.new(@source) unless @source.directory?
-      raise Basis::DirectoryAlreadyExists.new(@target) if @target.exist?
 
       @lifecycle = create_or_load_lifecycle
     end
@@ -36,7 +35,6 @@ def install(context={})
 
         if @lifecycle.install?(targetpath)
           targetpath.dirname.mkpath
-
           @lifecycle.installing(targetpath)
 
           if erb?(sourcepath)

lib/basis/installer/lifecycle.rb

@@ -7,11 +7,15 @@ def initialize(installer)
         @installer = installer
       end
 
-      def install?(path); true end
+      def install?(file)
+        true # FIXME: user prompt on overwrite, etc
+      end
 
-      def installing(path); end
+      def installing(file)
+      end
 
-      def installed(path); end
+      def installed(file)
+      end      
     end
   end
 end

spec/basis/installer_spec.rb

@@ -96,13 +96,18 @@
       (@target + "copy.txt").must be_exist
     end
 
-    it "prompts before overwriting files that already exist"
-    # def test_initialize_complains_about_targets_that_already_exist
-    #   assert_raise(Basis::DirectoryAlreadyExists) do
-    #     Basis::Installer.new(@static, FIXTURES_PATH)
-    #   end
-    # end
-
+    it "pings the lifecycle on files that already exist" do
+      @installer.install
+
+      def (@installer.lifecycle).install?(file)
+        raise Basis::FileAlreadyExists.new(file) if file.exist?
+        true
+      end
+
+      (@target + "monkeys.txt").must be_exist
+      lambda { @installer.install }.must raise_error(Basis::FileAlreadyExists)
+    end
+
     def valid_context
       { :greeting => "hai!", :foo => Struct.new(:bar).new("baz") } 
     end