use an rspec stub instead of a hook setter

Author: eli-darkly

lib/ldclient-rb/redis_store.rb

@@ -178,18 +178,12 @@ def stop
       end
     end
 
-    # exposed for testing
-    def clear_local_cache()
-      @cache.clear
-    end
+    private
 
     # exposed for testing
-    def set_transaction_hook(proc)
-      @transaction_hook = proc
+    def before_update_transaction(base_key, key)
     end
 
-    private
-
     def items_key(kind)
       @prefix + ":" + kind[:namespace]
     end
@@ -231,9 +225,7 @@ def update_with_versioning(kind, new_item)
         with_connection do |redis|
           redis.watch(base_key) do
             old_item = get_redis(kind, redis, key)
-            if @transaction_hook
-              @transaction_hook.call(base_key, key)
-            end
+            before_update_transaction(base_key, key)
             if old_item.nil? || old_item[:version] < new_item[:version]
               begin
                 result = redis.multi do |multi|

spec/redis_feature_store_spec.rb

@@ -32,16 +32,16 @@ def create_redis_store_uncached()
     include_examples "feature_store", method(:create_redis_store_uncached)
   end
 
-  def make_concurrent_modifier(other_client, flag, start_version, end_version)
+  def add_concurrent_modifier(store, other_client, flag, start_version, end_version)
     version_counter = start_version
-    Proc.new do |base_key, key|
+    expect(store).to receive(:before_update_transaction) { |base_key, key|
       if version_counter <= end_version
         new_flag = flag.clone
         new_flag[:version] = version_counter
         other_client.hset(base_key, key, new_flag.to_json)
         version_counter = version_counter + 1
       end
-    end
+    }.at_least(:once)
   end
 
   it "handles upsert race condition against external client with lower version" do
@@ -52,7 +52,7 @@ def make_concurrent_modifier(other_client, flag, start_version, end_version)
       flag = { key: "foo", version: 1 }
       store.init(LaunchDarkly::FEATURES => { flag[:key] => flag })
 
-      store.set_transaction_hook(make_concurrent_modifier(other_client, flag, 2, 4))
+      add_concurrent_modifier(store, other_client, flag, 2, 4)
 
       my_ver = { key: "foo", version: 10 }
       store.upsert(LaunchDarkly::FEATURES, my_ver)
@@ -71,7 +71,7 @@ def make_concurrent_modifier(other_client, flag, start_version, end_version)
       flag = { key: "foo", version: 1 }
       store.init(LaunchDarkly::FEATURES => { flag[:key] => flag })
 
-      store.set_transaction_hook(make_concurrent_modifier(other_client, flag, 3, 3))
+      add_concurrent_modifier(store, other_client, flag, 3, 3)
 
       my_ver = { key: "foo", version: 2 }
       store.upsert(LaunchDarkly::FEATURES, my_ver)