Fix circuit breaker recovery

- Use error_threshold_timeout when filtering observed errors
- Clear errors when closing circuit upon reaching success_threshold

Author: izuzak

lib/redis_client/circuit_breaker.rb

@@ -79,7 +79,7 @@ def refresh_state
 
     def record_error
       now = RedisClient.now
-      expiry = now - @error_timeout
+      expiry = now - @error_threshold_timeout
       @lock.synchronize do
         if @state == :closed
           @errors.reject! { |t| t < expiry }
@@ -100,6 +100,7 @@ def record_success
 
         @successes += 1
         if @successes >= @success_threshold
+          @errors.clear
           @state = :closed
         end
       end

test/redis_client/circuit_breaker_test.rb

@@ -21,6 +21,18 @@ def test_open_circuit_after_consecutive_errors
       assert_open @circuit_breaker
     end
 
+    def test_track_errors_during_error_threshold_window
+      assert_closed @circuit_breaker
+      (@circuit_breaker.error_threshold - 1).times do
+        record_error @circuit_breaker
+      end
+
+      travel(@circuit_breaker.error_threshold_timeout - 0.01) do
+        record_error @circuit_breaker
+        assert_open @circuit_breaker
+      end
+    end
+
     def test_allow_use_after_the_errors_timedout
       open_circuit @circuit_breaker
       assert_open @circuit_breaker