1 files changed, 46 insertions, 0 deletions
diff --git a/spec/ruby/core/mutex/lock_spec.rb b/spec/ruby/core/mutex/lock_spec.rb
new file mode 100644
index 0000000000..98deabe056
--- /dev/null
+++ b/spec/ruby/core/mutex/lock_spec.rb
@@ -0,0 +1,46 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+
+describe "Mutex#lock" do
+  before :each do
+    ScratchPad.clear
+  end
+
+  it "returns self" do
+    m = Mutex.new
+    m.lock.should == m
+    m.unlock
+  end
+
+  it "waits if the lock is not available" do
+    m = Mutex.new
+
+    m.lock
+
+    th = Thread.new do
+      m.lock
+      ScratchPad.record :after_lock
+    end
+
+    Thread.pass while th.status and th.status != "sleep"
+
+    ScratchPad.recorded.should be_nil
+    m.unlock
+    th.join
+    ScratchPad.recorded.should == :after_lock
+  end
+
+  # Unable to find a specific ticket but behavior change may be
+  # related to this ML thread.
+  it "raises a ThreadError when used recursively" do
+    m = Mutex.new
+
+    th = Thread.new do
+      m.lock
+      m.lock
+    end
+
+    lambda do
+      th.join
+    end.should raise_error(ThreadError)
+  end
+end