From 4ac143d1937e8d6f33162863a17c1b1db57687c1 Mon Sep 17 00:00:00 2001
From: Gabriel Sobrinho <gabriel.sobrinho@gmail.com>
Date: Tue, 12 Dec 2017 22:11:47 -0200
Subject: Support for connection pooling on mem cache store

---
 .../test/cache/stores/mem_cache_store_test.rb      | 74 ++++++++++++++++++++++
 1 file changed, 74 insertions(+)

(limited to 'activesupport/test/cache')

diff --git a/activesupport/test/cache/stores/mem_cache_store_test.rb b/activesupport/test/cache/stores/mem_cache_store_test.rb
index 99624caf8a..7f537c3bbf 100644
--- a/activesupport/test/cache/stores/mem_cache_store_test.rb
+++ b/activesupport/test/cache/stores/mem_cache_store_test.rb
@@ -5,6 +5,18 @@ require "active_support/cache"
 require_relative "../behaviors"
 require "dalli"
 
+# Emulates a latency on Dalli's back-end for the key latency to facilitate
+# connection pool testing.
+class SlowDalliClient < Dalli::Client
+  def get(key, options = {})
+    if key =~ /latency/
+      sleep 3
+    else
+      super
+    end
+  end
+end
+
 class MemCacheStoreTest < ActiveSupport::TestCase
   begin
     ss = Dalli::Client.new("localhost:11211").stats
@@ -34,6 +46,56 @@ class MemCacheStoreTest < ActiveSupport::TestCase
   include EncodedKeyCacheBehavior
   include AutoloadingCacheBehavior
 
+  def test_connection_pool
+    emulating_latency do
+      begin
+        cache = ActiveSupport::Cache.lookup_store(:mem_cache_store, pool_size: 2, pool_timeout: 1)
+        cache.clear
+
+        threads = []
+
+        assert_raises Timeout::Error do
+          # One of the three threads will fail in 1 second because our pool size
+          # is only two.
+          3.times do
+            threads << Thread.new do
+              cache.read("latency")
+            end
+          end
+
+          threads.each(&:join)
+        end
+      ensure
+        threads.each(&:kill)
+      end
+    end
+  end
+
+  def test_no_connection_pool
+    emulating_latency do
+      begin
+        cache = ActiveSupport::Cache.lookup_store(:mem_cache_store)
+        cache.clear
+
+        threads = []
+
+        assert_nothing_raised do
+          # Default connection pool size is 5, assuming 10 will make sure that
+          # the connection pool isn't used at all.
+          10.times do
+            threads << Thread.new do
+              cache.read("latency")
+            end
+          end
+
+          threads.each(&:join)
+        end
+      ensure
+        threads.each(&:kill)
+      end
+    end
+  end
+
   def test_raw_values
     cache = ActiveSupport::Cache.lookup_store(:mem_cache_store, raw: true)
     cache.clear
@@ -89,4 +151,16 @@ class MemCacheStoreTest < ActiveSupport::TestCase
     value << "bingo"
     assert_not_equal value, @cache.read("foo")
   end
+
+  private
+
+    def emulating_latency
+      old_client = Dalli.send(:remove_const, :Client)
+      Dalli.const_set(:Client, SlowDalliClient)
+
+      yield
+    ensure
+      Dalli.send(:remove_const, :Client)
+      Dalli.const_set(:Client, old_client)
+    end
 end
-- 
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