handle FileUtils.mkdir. Closes #37

Conflicts:

	test/fakefs_test.rb

lib/fakefs/fileutils.rb

@@ -7,6 +7,14 @@ module FakeFS
     end
     alias_method :mkpath, :mkdir_p
 
+    def mkdir(path)
+      parent = path.split('/')
+      parent.pop
+      raise Errno::ENOENT, "No such file or directory - #{path}" unless parent.join == "" || FileSystem.find(parent.join('/'))
+      raise Errno::EEXIST, "File exists - #{path}" if FileSystem.find(path)
+      FileSystem.add(path, FakeDir.new)
+    end
+
     def rmdir(list, options = {})
       list = [ list ] unless list.is_a?(Array)
       list.each do |l|

test/fakefs_test.rb

@@ -23,7 +23,7 @@ class FakeFSTest < Test::Unit::TestCase
     assert_equal 1, fs.files.size
   end
 
-  def test_can_create_directories
+  def test_can_create_directories_with_file_utils_mkdir_p
     FileUtils.mkdir_p("/path/to/dir")
     assert_kind_of FakeDir, FileSystem.fs['path']['to']['dir']
   end
@@ -33,6 +33,18 @@ class FakeFSTest < Test::Unit::TestCase
     assert_kind_of FakeDir, FileSystem.fs['path']['to']['dir']
   end
 
+  def test_can_create_directories_with_file_utils_mkdir
+    FileUtils.mkdir_p("/path/to/dir")
+    FileUtils.mkdir("/path/to/dir/subdir")
+    assert_kind_of FakeDir, FileSystem.fs['path']['to']['dir']['subdir']
+  end
+
+  def test_raises_error_when_creating_a_new_dir_with_mkdir_in_non_existent_path
+    assert_raises Errno::ENOENT do
+      FileUtils.mkdir("/this/path/does/not/exists/newdir")
+    end
+  end
+
   def test_can_create_directories_with_mkpath
     FileUtils.mkpath("/path/to/dir")
     assert_kind_of FakeDir, FileSystem.fs['path']['to']['dir']
@@ -83,6 +95,10 @@ class FakeFSTest < Test::Unit::TestCase
     assert File.exists?(path)
     FileUtils.mkdir_p("/path/to")
     assert File.exists?(path)
+    assert_raises Errno::EEXIST do
+      FileUtils.mkdir("/path/to")
+    end
+    assert File.exists?(path)
   end
 
   def test_can_create_symlinks