spec/ruby/core/mutex/synchronize_spec.rb


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66

require_relative '../../spec_helper'

describe "Mutex#synchronize" do
  it "wraps the lock/unlock pair in an ensure" do
    m1 = Mutex.new
    m2 = Mutex.new
    m2.lock
    synchronized = false

    th = Thread.new do
      -> do
        m1.synchronize do
          synchronized = true
          m2.lock
          raise Exception
        end
      end.should raise_error(Exception)
    end

    Thread.pass until synchronized

    m1.locked?.should be_true
    m2.unlock
    th.join
    m1.locked?.should be_false
  end

  it "blocks the caller if already locked" do
    m = Mutex.new
    m.lock
    -> { m.synchronize { } }.should block_caller
  end

  it "does not block the caller if not locked" do
    m = Mutex.new
    -> { m.synchronize { } }.should_not block_caller
  end

  it "blocks the caller if another thread is also in the synchronize block" do
    m = Mutex.new
    q1 = Queue.new
    q2 = Queue.new

    t = Thread.new {
      m.synchronize {
        q1.push :ready
        q2.pop
      }
    }

    q1.pop.should == :ready

    -> { m.synchronize { } }.should block_caller

    q2.push :done
    t.join
  end

  it "is not recursive" do
    m = Mutex.new

    m.synchronize do
      -> { m.synchronize { } }.should raise_error(ThreadError)
    end
  end
end