diff --git a/lib/redlock/client.rb b/lib/redlock/client.rb
index 9a2e839..f538eeb 100644
--- a/lib/redlock/client.rb
+++ b/lib/redlock/client.rb
@@ -168,13 +168,17 @@ def initialize(connection)
 
       def lock(resource, val, ttl, allow_new_lock)
         recover_from_script_flush do
-          @redis.call('EVALSHA', Scripts::LOCK_SCRIPT_SHA, 1, resource, val, ttl, allow_new_lock)
+          @redis.with { |conn|
+            conn.call('EVALSHA', Scripts::LOCK_SCRIPT_SHA, 1, resource, val, ttl, allow_new_lock)
+          }
         end
       end
 
       def unlock(resource, val)
         recover_from_script_flush do
-          @redis.call('EVALSHA', Scripts::UNLOCK_SCRIPT_SHA, 1, resource, val)
+          @redis.with { |conn|
+            conn.call('EVALSHA', Scripts::UNLOCK_SCRIPT_SHA, 1, resource, val)
+          }
         end
       rescue
         # Nothing to do, unlocking is just a best-effort attempt.
@@ -182,7 +186,9 @@ def unlock(resource, val)
 
       def get_remaining_ttl(resource)
         recover_from_script_flush do
-          @redis.call('EVALSHA', Scripts::PTTL_SCRIPT_SHA, 1, resource)
+          @redis.with { |conn|
+            conn.call('EVALSHA', Scripts::PTTL_SCRIPT_SHA, 1, resource)
+          }
         end
       rescue RedisClient::ConnectionError
         nil
diff --git a/spec/client_spec.rb b/spec/client_spec.rb
index 6b99d09..758a5e3 100644
--- a/spec/client_spec.rb
+++ b/spec/client_spec.rb
@@ -5,7 +5,21 @@
 RSpec.describe Redlock::Client do
   # It is recommended to have at least 3 servers in production
   let(:lock_manager_opts) { { retry_count: 3 } }
-  let(:lock_manager) { Redlock::Client.new(Redlock::Client::DEFAULT_REDIS_URLS, lock_manager_opts) }
+  let(:redis_urls_or_clients) {
+    urls = Redlock::Client::DEFAULT_REDIS_URLS
+    if rand(0..1).zero?
+      RSpec.configuration.reporter.message "variant: client urls"
+      urls
+    else
+      RSpec.configuration.reporter.message "variant: client objects"
+      urls.map {|url|
+        ConnectionPool.new { RedisClient.new(url: url) }
+      }
+    end
+  }
+  let(:lock_manager) {
+    Redlock::Client.new(redis_urls_or_clients, lock_manager_opts)
+  }
   let(:redis_client) { RedisClient.new(url: "redis://#{redis1_host}:#{redis1_port}") }
   let(:resource_key) { SecureRandom.hex(3)  }
   let(:ttl) { 1000 }
@@ -37,9 +51,10 @@ def redis.with
 
     it 'accepts ConnectionPool objects' do
       pool = ConnectionPool.new { RedisClient.new(url: "redis://#{redis1_host}:#{redis1_port}") }
-      redlock = Redlock::Client.new([pool])
+      _redlock = Redlock::Client.new([pool])
 
       lock_info = lock_manager.lock(resource_key, ttl)
+      expect(lock_info).to be_a(Hash)
       expect(resource_key).to_not be_lockable(lock_manager, ttl)
       lock_manager.unlock(lock_info)
     end
@@ -48,7 +63,7 @@ def redis.with
       redis_client.call('SCRIPT', 'FLUSH')
 
       pool = ConnectionPool.new { RedisClient.new(url: "redis://#{redis1_host}:#{redis1_port}") }
-      redlock = Redlock::Client.new([pool])
+      _redlock = Redlock::Client.new([pool])
 
       raw_info = redis_client.call('INFO')
       number_of_cached_scripts = raw_info[/number_of_cached_scripts\:\d+/].split(':').last
@@ -197,7 +212,7 @@ def redis.with
           2000
         end
 
-        lock_manager = Redlock::Client.new(Redlock::Client::DEFAULT_REDIS_URLS, retry_count: 1, retry_delay: retry_delay)
+        lock_manager = Redlock::Client.new(redis_urls_or_clients, retry_count: 1, retry_delay: retry_delay)
         another_lock_info = lock_manager.lock(resource_key, ttl)
 
         expect(lock_manager).to receive(:sleep) do |sleep|
@@ -272,7 +287,9 @@ def redis.with
     context 'when script cache has been flushed' do
       before(:each) do
         @manipulated_instance = lock_manager.instance_variable_get(:@servers).first
-        @manipulated_instance.instance_variable_get(:@redis).call('SCRIPT', 'FLUSH')
+        @manipulated_instance.instance_variable_get(:@redis).with { |conn|
+          conn.call('SCRIPT', 'FLUSH')
+        }
       end
 
       it 'does not raise a RedisClient::CommandError: NOSCRIPT error' do
@@ -475,7 +492,7 @@ def redis.with
 
         # Replace redis with unreachable instance
         redis_instance = lock_manager.instance_variable_get(:@servers).first
-        old_redis = redis_instance.instance_variable_get(:@redis)
+        _old_redis = redis_instance.instance_variable_get(:@redis)
         redis_instance.instance_variable_set(:@redis, unreachable_redis)
 
         expect {
diff --git a/spec/testing_spec.rb b/spec/testing_spec.rb
index 9fc881b..41a4a6f 100644
--- a/spec/testing_spec.rb
+++ b/spec/testing_spec.rb
@@ -11,7 +11,7 @@
   describe '(testing mode)' do
     describe 'try_lock_instances' do
       context 'when testing with bypass mode' do
-        before { lock_manager.testing_mode = :bypass }
+        before { Redlock::Client.testing_mode = :bypass }
 
         it 'bypasses the redis servers' do
           expect(lock_manager).to_not receive(:try_lock_instances_without_testing)
@@ -22,7 +22,7 @@
       end
 
       context 'when testing with fail mode' do
-        before { lock_manager.testing_mode = :fail }
+        before { Redlock::Client.testing_mode = :fail }
 
         it 'fails' do
           expect(lock_manager).to_not receive(:try_lock_instances_without_testing)
@@ -33,7 +33,7 @@
       end
 
       context 'when testing is disabled' do
-        before { lock_manager.testing_mode = nil }
+        before { Redlock::Client.testing_mode = nil }
 
         it 'works as usual' do
           expect(lock_manager).to receive(:try_lock_instances_without_testing)