Tighten API, add spec for recovery, keep mutex semantics

spec/components/distributed_mutex_spec.rb

@@ -3,34 +3,47 @@ require_dependency 'distributed_mutex'
 
 describe DistributedMutex do
   it "allows only one mutex object to have the lock at a time" do
-    m1 = DistributedMutex.new("test_mutex_key")
-    m2 = DistributedMutex.new("test_mutex_key")
-
-    m1.get_lock
-    m2.got_lock.should be_false
-
-    t = Thread.new do
-      m2.get_lock
+    mutexes = (1..10).map do
+      DistributedMutex.new("test_mutex_key")
     end
 
-    m1.release_lock
-    t.join
-    m2.got_lock.should == true
-  end
-
-  it "synchronizes correctly" do
-    array = []
-    t = Thread.new do
-      DistributedMutex.new("correct_sync").synchronize do
-        sleep 0.01
-        array.push 1
+    x = 0
+    mutexes.map do |m|
+      Thread.new do
+        m.synchronize do
+          y = x
+          sleep 0.001
+          x = y + 1
+        end
       end
-    end
-    sleep 0.005
-    DistributedMutex.new("correct_sync").synchronize do
-      array.push 2
-    end
-    t.join
-    array.should == [1, 2]
+    end.map(&:join)
+
+    x.should == 10
   end
+
+  it "handles auto cleanup correctly" do
+    m = DistributedMutex.new("test_mutex_key")
+
+    $redis.setnx "test_mutex_key", Time.now.to_i - 1
+
+
+    start = Time.now.to_i
+    m.synchronize do
+      "nop"
+    end
+
+    # no longer than a second
+    Time.now.to_i.should <= start + 1
+  end
+
+  it "maintains mutex semantics" do
+    m = DistributedMutex.new("test_mutex_key")
+
+    lambda {
+      m.synchronize do
+        m.synchronize{}
+      end
+    }.should raise_error(ThreadError)
+  end
+
 end