added probe specs

Author: mighe

spec/concurrent/channel/probe_spec.rb

@@ -3,6 +3,47 @@
 module Concurrent
 
   describe Probe do
-    it 'should be written'
+
+    let(:probe) { Probe.new }
+
+    describe '#set_unless_assigned' do
+      context 'empty probe' do
+        it 'assigns the value' do
+          probe.set_unless_assigned(32)
+          probe.value.should eq 32
+        end
+
+        it 'returns true' do
+          probe.set_unless_assigned('hi').should eq true
+        end
+      end
+
+      context 'fulfilled probe' do
+        before(:each) { probe.set(27) }
+
+        it 'does not assign the value' do
+          probe.set_unless_assigned(88)
+          probe.value.should eq 27
+        end
+
+        it 'returns false' do
+          probe.set_unless_assigned('hello').should eq false
+        end
+      end
+
+      context 'rejected probe' do
+        before(:each) { probe.fail }
+
+        it 'does not assign the value' do
+          probe.set_unless_assigned(88)
+          probe.should be_rejected
+        end
+
+        it 'returns false' do
+          probe.set_unless_assigned('hello').should eq false
+        end
+      end
+    end
+
   end
 end