test_output_as_buffered_secondary: add secondary_chunk_count_metrics tests

Signed-off-by: Shizuo Fujita <fujita@clear-code.com>

Author: Watson1978

test/plugin/test_output_as_buffered_secondary.rb

@@ -308,6 +308,7 @@ def dummy_event_stream
 
       assert_equal 0, @i.write_count
       assert_equal 0, @i.num_errors
+      assert_equal 0, @i.instance_variable_get(:@secondary_chunk_count_metrics).get
 
       @i.enqueue_thread_wait
       @i.flush_thread_wakeup
@@ -348,6 +349,8 @@ def dummy_event_stream
       assert{ @i.write_count > prev_write_count }
       assert{ @i.num_errors == prev_num_errors }
 
+      assert{ @i.instance_variable_get(:@secondary_chunk_count_metrics).get > 0 }
+
       assert_nil @i.retry
 
       assert_equal [ 'test.tag.1', event_time('2016-04-13 18:33:00').to_i, {"name" => "moris", "age" => 36, "message" => "data1"} ], written[0]
@@ -388,6 +391,7 @@ def dummy_event_stream
 
       assert_equal 0, @i.write_count
       assert_equal 0, @i.num_errors
+      assert_equal 0, @i.instance_variable_get(:@secondary_chunk_count_metrics).get
 
       @i.enqueue_thread_wait
       @i.flush_thread_wakeup
@@ -443,6 +447,8 @@ def dummy_event_stream
       assert{ @i.buffer.dequeued[chunks[0].unique_id].nil? }
       assert{ chunks.first.empty? }
 
+      assert{ @i.instance_variable_get(:@secondary_chunk_count_metrics).get > 0 }
+
       assert_nil @i.retry
 
       logs = @i.log.out.logs
@@ -737,6 +743,7 @@ def dummy_event_stream
 
       assert_equal 0, @i.write_count
       assert_equal 0, @i.num_errors
+      assert_equal 0, @i.instance_variable_get(:@secondary_chunk_count_metrics).get
 
       @i.enqueue_thread_wait
       @i.flush_thread_wakeup
@@ -765,6 +772,8 @@ def dummy_event_stream
         prev_write_count = @i.write_count
       end
 
+      assert{ @i.instance_variable_get(:@secondary_chunk_count_metrics).get > 0 }
+
       # retry_timeout == 60(sec), retry_secondary_threshold == 0.8
 
       assert{ now >= first_failure + 60 * 0.8 }