From 94d19cd0b27285de22b725b333c9f1a7258ba968 Mon Sep 17 00:00:00 2001
From: Ian Ker-Seymer <i.kerseymer@gmail.com>
Date: Tue, 6 Jun 2017 16:19:22 -0400
Subject: [PATCH 1/3] Add specs for Promise#zip/Promise.zip ordering

---
 spec/concurrent/promise_spec.rb | 42 +++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/spec/concurrent/promise_spec.rb b/spec/concurrent/promise_spec.rb
index 3fb35b276..ae6fa11b9 100644
--- a/spec/concurrent/promise_spec.rb
+++ b/spec/concurrent/promise_spec.rb
@@ -368,6 +368,27 @@ def get_ivar_from_args(opts)
 
         expect(composite).to be_rejected
       end
+
+      it 'preserves ordering of the executed promises' do
+        promise1 = Promise.execute do
+          # resolves after the second promise
+          sleep 0.2
+          'one'
+        end
+
+        promise2 = Promise.execute do
+          sleep 0.1
+          'two'
+        end
+
+        promise3 = Promise.execute do
+          'three'
+        end
+
+        result = promise1.zip(promise2, promise3).value
+
+        expect(result).to eql(['one', 'two', 'three'])
+      end
     end
 
     describe '.zip' do
@@ -386,6 +407,27 @@ def get_ivar_from_args(opts)
 
         expect(composite).to be_rejected
       end
+
+      it 'preserves ordering of the executed promises' do
+        promise1 = Promise.execute do
+          # resolves after the second promise
+          sleep 0.2
+          'one'
+        end
+
+        promise2 = Promise.execute do
+          sleep 0.1
+          'two'
+        end
+
+        promise3 = Promise.execute do
+          'three'
+        end
+
+        result = Promise.zip(promise1, promise2, promise3).value
+
+        expect(result).to eql(['one', 'two', 'three'])
+      end
     end
 
     describe 'aggregators' do

From 47befe994a6792af258aa0fb1396ca4eda8dd5ca Mon Sep 17 00:00:00 2001
From: Ian Ker-Seymer <i.kerseymer@gmail.com>
Date: Wed, 15 Nov 2017 23:24:47 -0500
Subject: [PATCH 2/3] Use CVs to test ordering of Promise#zip resolution

---
 spec/concurrent/promise_spec.rb | 42 ++++++++++++++++++++++-----------
 1 file changed, 28 insertions(+), 14 deletions(-)

diff --git a/spec/concurrent/promise_spec.rb b/spec/concurrent/promise_spec.rb
index ae6fa11b9..f17828657 100644
--- a/spec/concurrent/promise_spec.rb
+++ b/spec/concurrent/promise_spec.rb
@@ -370,24 +370,38 @@ def get_ivar_from_args(opts)
       end
 
       it 'preserves ordering of the executed promises' do
-        promise1 = Promise.execute do
-          # resolves after the second promise
-          sleep 0.2
-          'one'
-        end
+        10.times do
+          running = Mutex.new
+          cond = ConditionVariable.new
+          cond2 = ConditionVariable.new
+          executor = SimpleExecutorService.new
 
-        promise2 = Promise.execute do
-          sleep 0.1
-          'two'
-        end
+          p1 = Concurrent::Promise.execute(executor: executor) do
+            running.synchronize do
+              cond.wait(running)
+              'one'
+            end
+          end
 
-        promise3 = Promise.execute do
-          'three'
-        end
+          p2 = Concurrent::Promise.execute(executor: executor) do
+            running.synchronize do
+              cond2.wait(running)
+              'two'
+            end
+          end
 
-        result = promise1.zip(promise2, promise3).value
+          p3 = Concurrent::Promise.execute(executor: executor) do
+            running.synchronize do
+              'three'
+            end
+          end
 
-        expect(result).to eql(['one', 'two', 'three'])
+          cond2.signal
+          cond.signal
+
+          result = Concurrent::Promise.zip(p1, p2, p3).value
+          expect(result) .to eq(['one', 'two', 'three'])
+        end
       end
     end
 

From 8720d173da1245ce95d3d7949499d4a8536c4ad5 Mon Sep 17 00:00:00 2001
From: Petr Chalupa <git@pitr.ch>
Date: Sat, 24 Feb 2018 21:44:38 +0100
Subject: [PATCH 3/3] Use CountDownLatch

---
 spec/concurrent/promise_spec.rb | 35 +++++++++------------------------
 1 file changed, 9 insertions(+), 26 deletions(-)

diff --git a/spec/concurrent/promise_spec.rb b/spec/concurrent/promise_spec.rb
index f17828657..c49930014 100644
--- a/spec/concurrent/promise_spec.rb
+++ b/spec/concurrent/promise_spec.rb
@@ -371,36 +371,19 @@ def get_ivar_from_args(opts)
 
       it 'preserves ordering of the executed promises' do
         10.times do
-          running = Mutex.new
-          cond = ConditionVariable.new
-          cond2 = ConditionVariable.new
+          latch1 = CountDownLatch.new
+          latch2 = CountDownLatch.new
           executor = SimpleExecutorService.new
 
-          p1 = Concurrent::Promise.execute(executor: executor) do
-            running.synchronize do
-              cond.wait(running)
-              'one'
-            end
-          end
-
-          p2 = Concurrent::Promise.execute(executor: executor) do
-            running.synchronize do
-              cond2.wait(running)
-              'two'
-            end
-          end
-
-          p3 = Concurrent::Promise.execute(executor: executor) do
-            running.synchronize do
-              'three'
-            end
-          end
+          p1 = Concurrent::Promise.execute(executor: executor) { latch1.wait; 'one' }
+          p2 = Concurrent::Promise.execute(executor: executor) { latch2.wait; 'two' }
+          p3 = Concurrent::Promise.execute(executor: executor) { 'three' }
 
-          cond2.signal
-          cond.signal
+          latch1.count_down
+          latch2.count_down
 
-          result = Concurrent::Promise.zip(p1, p2, p3).value
-          expect(result) .to eq(['one', 'two', 'three'])
+          result = Concurrent::Promise.zip(p1, p2, p3).value!
+          expect(result).to eq(['one', 'two', 'three'])
         end
       end
     end