```ruby
require 'helper'

class SignalHandlerTest < Test::Unit::TestCase
  def setup
    @exp = Expectr.new("bc", flush_buffer: false, timeout: 1)
  end

  def test_winsz_change
    winsize = $stdout.winsize
    [
      Thread.new {
        sleep 0.5
        @exp.interact!.join
      },
      Thread.new {
        sleep 1
        @exp.flush_buffer=false
        assert_nothing_raised do
          $stdout.winsize = [10,10]
        end
        sleep 0.1
        assert_equal [10,10], @exp.winsize
        @exp.puts("quit")
      }
    ].each {|x| x.join}

    $stdout.winsize = winsize
  end

  def test_kill_process
    assert_equal true, @exp.kill!
    assert_equal 0, @exp.pid
    assert_raises(Expectr::ProcessError) { @exp.send("test\n") }
  end
end
```

Update signal tests for readability
user
```ruby
require 'helper'

class SignalHandlerTest < Test::Unit::TestCase
  def setup
    @exp = Expectr.new("bc", flush_buffer: false, timeout: 1)
  end

  def test_winsz_change
    winsize = $stdout.winsize
    [
      Thread.new {
        sleep 0.5
        @exp.interact!.join
      },
      Thread.new {
        sleep 1
        @exp.flush_buffer = false
        assert_nothing_raised do
          $stdout.winsize = [10, 10]
        end
        sleep 0.1
        assert_equal([10, 10], @exp.winsize)
        @exp.puts("quit")
      }
    ].each { |x| x.join }

    $stdout.winsize = winsize
  end

  def test_kill_process
    assert_equal(true, @exp.kill!)
    sleep 0.5
    assert_equal(0, @exp.pid)
    assert_raises(Expectr::ProcessError) { @exp.send("test\n") }
  end
end
```
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