require 'test/unit'

class TestTrace < Test::Unit::TestCase
  def test_trace
    $x = 1234
    $y = 0
    trace_var :$x, proc{$y = $x}
    $x = 40414
    assert_equal($x, $y)

    untrace_var :$x
    $x = 19660208
    assert_not_equal($x, $y)

    trace_var :$x, proc{$x *= 2}
    $x = 5
    assert_equal(10, $x)

    untrace_var :$x
  end

  def test_trace_tainted_proc
    $x = 1234
    s = proc { $y = :foo }
    trace_var :$x, s
    s.taint
    $x = 42
    assert_equal(:foo, $y)
  ensure
    untrace_var :$x
  end

  def test_trace_proc_that_raises_exception
    $x = 1234
    trace_var :$x, proc { raise }
    assert_raise(RuntimeError) { $x = 42 }
  ensure
    untrace_var :$x
  end

  def test_trace_string
    $x = 1234
    trace_var :$x, "$y = :bar"
    $x = 42
    assert_equal(:bar, $y)
  ensure
    untrace_var :$x
  end
end
