1 files changed, 60 insertions, 0 deletions
diff --git a/activesupport/test/file_evented_update_checker_test.rb b/activesupport/test/file_evented_update_checker_test.rb
index 10b7a5c979..727b99958e 100644
--- a/activesupport/test/file_evented_update_checker_test.rb
+++ b/activesupport/test/file_evented_update_checker_test.rb
@@ -1,6 +1,7 @@
 require 'abstract_unit'
 require 'fileutils'
 require 'thread'
+require 'pathname'
 require 'file_update_checker_with_enumerable_test_cases'
 
 class FileEventedUpdateCheckerTest < ActiveSupport::TestCase
@@ -10,3 +11,62 @@ class FileEventedUpdateCheckerTest < ActiveSupport::TestCase
     ActiveSupport::FileEventedUpdateChecker.new(files, dirs, &block)
   end
 end
+
+class FileEventedUpdateCheckerPathHelperTest < ActiveSupport::TestCase
+  def pn(path)
+    Pathname.new(path)
+  end
+
+  setup do
+    @ph = ActiveSupport::FileEventedUpdateChecker::PathHelper.new
+  end
+
+  test '#xpath returns the expanded path as a Pathname object' do
+    assert_equal pn(__FILE__).expand_path, @ph.xpath(__FILE__)
+  end
+
+  test '#normalize_extension returns a bare extension as is' do
+    assert_equal 'rb', @ph.normalize_extension('rb')
+  end
+
+  test '#normalize_extension removes a leading dot' do
+    assert_equal 'rb', @ph.normalize_extension('.rb')
+  end
+
+  test '#normalize_extension supports symbols' do
+    assert_equal 'rb', @ph.normalize_extension(:rb)
+  end
+
+  test '#longest_common_subpath finds the longest common subpath, if there is one' do
+    paths = %w(
+      /foo/bar
+      /foo/baz
+      /foo/bar/baz/woo/zoo
+    ).map {|path| pn(path)}
+
+    assert_equal pn('/foo'), @ph.longest_common_subpath(paths)
+  end
+
+  test '#longest_common_subpath returns the root directory as an edge case' do
+    paths = %w(
+      /foo/bar
+      /foo/baz
+      /foo/bar/baz/woo/zoo
+      /wadus
+    ).map {|path| pn(path)}
+
+    assert_equal pn('/'), @ph.longest_common_subpath(paths)
+  end
+
+  test '#longest_common_subpath returns nil for an empty collection' do
+    assert_nil @ph.longest_common_subpath([])
+  end
+
+  test '#existing_parent returns the most specific existing ascendant' do
+    wd = Pathname.getwd
+
+    assert_equal wd, @ph.existing_parent(wd)
+    assert_equal wd, @ph.existing_parent(wd.join('non-existing/directory'))
+    assert_equal pn('/'), @ph.existing_parent(pn('/non-existing/directory'))
+  end
+end