Initial attempt at ConditionVariable implementation.

spec/process_shared/condition_variable_spec.rb

@@ -0,0 +1,67 @@
+require 'spec_helper'
+
+require 'process_shared/condition_variable'
+
+module ProcessShared
+  describe ConditionVariable do
+    it 'runs the example of Ruby Stdlib ConditionVariable' do
+      mutex = Mutex.new
+      resource = ConditionVariable.new
+
+      a = fork {
+        mutex.synchronize {
+          resource.wait(mutex)
+        }
+        Kernel.exit!
+      }
+      
+      b = fork {
+        mutex.synchronize {
+          resource.signal
+        }
+        Kernel.exit!
+      }
+
+      ::Process.wait(a)
+      ::Process.wait(b)
+    end
+
+    it 'broadcasts to multiple processes' do
+      mutex = Mutex.new
+      cond = ConditionVariable.new
+      mem = SharedMemory.new(:int)
+      mem.write_int(0)
+
+      pids = []
+      10.times do
+        pids << fork do
+          mutex.synchronize {
+            cond.wait(mutex)
+            mem.write_int(mem.read_int + 1)
+          }
+          Kernel.exit!
+        end
+      end
+
+      sleep 0.2               # hopefully they are all waiting...
+      mutex.synchronize {
+        cond.broadcast
+      }
+
+      pids.each { |p| ::Process.wait(p) }
+
+      mem.read_int.must_equal(10)
+    end
+
+    it 'stops waiting after timeout' do
+      mutex = Mutex.new
+      cond = ConditionVariable.new
+
+      mutex.synchronize {
+        start = Time.now.to_f
+        cond.wait(mutex, 0.1)
+        (Time.now.to_f - start).must be_gte(0.1)
+      }
+    end
+  end
+end