1 files changed, 39 insertions, 0 deletions
diff --git a/spec/ruby/core/mutex/synchronize_spec.rb b/spec/ruby/core/mutex/synchronize_spec.rb
index 206b14e828..e3dad508b8 100644
--- a/spec/ruby/core/mutex/synchronize_spec.rb
+++ b/spec/ruby/core/mutex/synchronize_spec.rb
@@ -24,4 +24,43 @@ describe "Mutex#synchronize" do
     th.join
     m1.locked?.should be_false
   end
+
+  it "blocks the caller if already locked" do
+    m = Mutex.new
+    m.lock
+    lambda { m.synchronize { } }.should block_caller
+  end
+
+  it "does not block the caller if not locked" do
+    m = Mutex.new
+    lambda { 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
+
+    lambda { m.synchronize { } }.should block_caller
+
+    q2.push :done
+    t.join
+  end
+
+  it "is not recursive" do
+    m = Mutex.new
+
+    m.synchronize do
+      lambda { m.synchronize { } }.should raise_error(ThreadError)
+    end
+  end
 end