Add the write-during-migration test to the acceptance test run

tests/acceptance/test_write_during_migration.rb

@@ -0,0 +1,128 @@
+#!/usr/bin/env ruby
+
+require 'test/unit'
+require 'flexnbd/fake_source'
+require 'socket'
+require 'fileutils'
+require 'tmpdir'
+
+Thread.abort_on_exception = true
+
+class TestWriteDuringMigration < Test::Unit::TestCase
+
+  def setup
+    @flexnbd = File.expand_path("../../build/flexnbd")
+
+    raise "No binary!" unless File.executable?( @flexnbd )
+    raise "No trickle!" unless system "which trickle > /dev/null"
+
+
+    @size = 20*1024*1024 # 20MB
+    @write_data = "foo!" * 2048 # 8K write
+    @source_port = 9990
+    @dest_port = 9991
+    @source_sock = "src.sock"
+    @dest_sock = "dst.sock"
+    @source_file = "src.file"
+    @dest_file = "dst.file"
+  end
+
+
+  def teardown
+    [@dst_proc, @src_proc].each do |pid|
+      if pid
+        Process.kill( "KILL", pid ) rescue nil
+      end
+    end
+  end
+
+
+  def launch_servers
+    @dst_proc = fork() {
+      cmd = "#{@flexnbd} listen -l 127.0.0.1 -p #{@dest_port} -f #{@dest_file} -s #{@dest_sock}"
+      exec cmd
+    }
+
+    @src_proc = fork() {
+      cmd = "#{@flexnbd} serve -l 127.0.0.1 -p #{@source_port} -f #{@source_file} -s #{@source_sock}"
+      exec cmd
+    }
+    begin
+      awaiting = nil
+      Timeout.timeout(10) do
+        awaiting = :source
+        sleep 0.1 while !File.exists?( @source_sock ) 
+        awaiting = :dest
+        sleep 0.1 while !File.exists?( @dest_sock )
+      end
+    rescue Timeout::Error
+      case awaiting
+      when :source
+        fail "Couldn't get a source socket."
+      when :dest
+        fail "Couldn't get a destination socket."
+      else
+        fail "Something went wrong I don't understand."
+      end
+    end
+  end
+
+
+  def make_files()
+    FileUtils.touch(@source_file)
+    File.truncate(@source_file, @size)
+    FileUtils.touch(@dest_file)
+    File.truncate(@dest_file, @size)
+
+    File.open(@source_file, "wb"){|f| f.write "a"*@size }
+  end
+
+
+  def start_mirror
+    UNIXSocket.open(@source_sock) {|sock|
+      sock.write(["mirror", "127.0.0.1", @dest_port.to_s, "unlink"].join("\x0A") + "\x0A\x0A")
+      sock.flush
+      rsp = sock.readline
+    }
+  end
+
+
+  def wait_for_quit()
+    Timeout.timeout( 10 ) do
+      start_time =  Time.now
+      dst_result = Process::waitpid2(@dst_proc)
+      src_result = Process::waitpid2(@src_proc)
+    end
+
+  end
+
+
+  def test_write_during_migration
+
+    Dir.mktmpdir() do |tmpdir|
+      Dir.chdir( tmpdir ) do
+        make_files()
+        
+        launch_servers()
+
+        src_writer = Thread.new do
+          client = FlexNBD::FakeSource.new( "127.0.0.1", @source_port, "Timed out connecting" )
+          loop do
+            begin
+              client.write(0, @write_data)
+            rescue => err
+              # We expect a broken write at some point, so ignore it
+              break
+            end
+          end
+        end
+
+        start_mirror()
+        wait_for_quit()
+        src_writer.join
+      end
+    end
+  end
+
+
+end