test in_tail: use safer method to cleanup

This PR aims to fix in_tail test cases on Windows.

On Windows, when the file or directory is removed and created
frequently, there is a case that creating file or directory will fail.
This situation is caused by pending file or directory deletion which
is mentioned on win32 API document.

ref. https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilea#files

As a workaround, execute rename and remove method.

Signed-off-by: Kentaro Hayashi <kenhys@gmail.com>

test/plugin/test_in_tail.rb

@@ -6,6 +6,8 @@
 require 'net/http'
 require 'flexmock/test_unit'
 require 'timecop'
+require 'tmpdir'
+require 'securerandom'
 
 class TailInputTest < Test::Unit::TestCase
   include FlexMock::TestCase
@@ -22,28 +24,42 @@ def teardown
   end
 
   def cleanup_directory(path)
+    unless Dir.exist?(path)
+      FileUtils.mkdir_p(path)
+      return
+    end
+
+    dir = File.join(Dir.tmpdir, SecureRandom.hex(10))
     begin
-      FileUtils.rm_f(path, secure: true)
+      files = Dir.glob("*", base: path)
+      if files.empty?
+        FileUtils.mv(path, dir)
+      else
+        files.each do |name|
+          FileUtils.rm_rf(File.join(path, name))
+        end
+      end
+      GC.start(full_mark: true, immediate_mark: true, immediate_sweep: true)
+      FileUtils.rm_rf(dir, secure: true)
     rescue ArgumentError
-      FileUtils.rm_f(path) # For Ruby 2.6 or before.
-    end
-    if File.exist?(path)
-      FileUtils.remove_entry_secure(path, true)
+      FileUtils.rm_rf(dir) # For Ruby 2.6 or before.
     end
     FileUtils.mkdir_p(path)
   end
 
   def cleanup_file(path)
+    file = File.join(Dir.tmpdir, SecureRandom.hex(10))
     begin
-      FileUtils.rm_f(path, secure: true)
+      FileUtils.mv(path, file)
+      FileUtils.rm_rf(file, secure: true)
     rescue ArgumentError
-      FileUtils.rm_f(path) # For Ruby 2.6 or before.
+      FileUtils.rm_rf(file) # For Ruby 2.6 or before.
     end
-    if File.exist?(path)
+    if File.exist?(file)
       # ensure files are closed for Windows, on which deleted files
       # are still visible from filesystem
       GC.start(full_mark: true, immediate_mark: true, immediate_sweep: true)
-      FileUtils.remove_entry_secure(path, true)
+      FileUtils.remove_entry_secure(file, true)
     end
   end