diff --git a/test/helper.rb b/test/helper.rb
index 77b74ed..04e96f0 100644
--- a/test/helper.rb
+++ b/test/helper.rb
@@ -1,28 +1,10 @@
-require 'rubygems'
-require 'bundler'
+require "test-unit"
+require "fluent/test"
 
-require 'test/unit'
-require 'test/unit/rr'
-
-$LOAD_PATH.unshift(File.join(File.dirname(__FILE__), '..', 'lib'))
-$LOAD_PATH.unshift(File.dirname(__FILE__))
-
-require 'fluent/test'
-
-class Test::Unit::TestCase
-  def capture_log(log)
-    if defined?(Fluent::Test::TestLogger) and log.is_a?(Fluent::Test::TestLogger) # v0.14
-      yield
-      log.out.logs.join("\n")
-    else
-      begin
-        tmp = log.out
-        log.out = StringIO.new
-        yield
-        return log.out.string
-      ensure
-        log.out = tmp
-      end
+module Helper
+  def normalize_logs(logs)
+    logs.collect do |log|
+      log.gsub(/\A\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2} [-+]\d{4} \[info\]: /, "") 
     end
   end
 end
diff --git a/test/plugin/test_filter_flowcounter_simple.rb b/test/plugin/test_filter_flowcounter_simple.rb
index a33961b..69a749b 100644
--- a/test/plugin/test_filter_flowcounter_simple.rb
+++ b/test/plugin/test_filter_flowcounter_simple.rb
@@ -4,6 +4,7 @@
 
 class FlowCounterSimpleFilterTest < Test::Unit::TestCase
   include Fluent
+  include Helper
 
   def setup
     Fluent::Test.setup
@@ -25,9 +26,10 @@ def test_filter
       msgs << {'message'=> 'b' * 100}
     end
     d = create_driver
-    filtered, out = filter(d, msgs)
+    filtered, logs = filter(d, msgs)
     assert_equal msgs, filtered
-    assert { out.include?("count:20") }
+    assert_equal(["plugin:filter_flowcounter_simple\tcount:20\tindicator:num\tunit:second\n"],
+                 normalize_logs(logs))
   end
 
   private
@@ -37,10 +39,8 @@ def filter(d,  msgs)
       msgs.each {|msg|
         d.feed(msg)
       }
-    }
-    out = capture_log(d.instance.log) do
       d.instance.flush_emit(0)
-    end
-    [d.filtered_records, out]
+    }
+    [d.filtered_records, d.logs]
   end
 end
diff --git a/test/plugin/test_out_flowcounter_simple.rb b/test/plugin/test_out_flowcounter_simple.rb
index 78ce5ea..1cd6770 100644
--- a/test/plugin/test_out_flowcounter_simple.rb
+++ b/test/plugin/test_out_flowcounter_simple.rb
@@ -3,6 +3,8 @@
 require 'fluent/plugin/out_flowcounter_simple'
 
 class FlowCounterSimpleOutputTest < Test::Unit::TestCase
+  include Helper
+
   def setup
     Fluent::Test.setup
   end
@@ -38,9 +40,10 @@ def test_num
         d1.feed({'message'=> 'b' * 100})
         d1.feed({'message'=> 'c' * 100})
       end
+      d1.instance.flush_emit(60)
     end
-    out = capture_log(d1.instance.log) { d1.instance.flush_emit(60) }
-    assert { out.include?("count:30") }
+    assert_equal(["plugin:out_flowcounter_simple\tcount:30\tindicator:num\tunit:second\n"],
+                 normalize_logs(d1.logs))
   end
 
   def test_byte
@@ -51,9 +54,10 @@ def test_byte
         d1.feed({'message'=> 'b' * 100})
         d1.feed({'message'=> 'c' * 100})
       end
+      d1.instance.flush_emit(60)
     end
-    out = capture_log(d1.instance.log) { d1.instance.flush_emit(60) }
-    assert { out =~ /count:\d+\tindicator:byte\tunit:second/ }
+    assert_equal(["plugin:out_flowcounter_simple\tcount:3330\tindicator:byte\tunit:second\n"],
+                 normalize_logs(d1.logs))
   end
 
   def test_comment
@@ -64,8 +68,9 @@ def test_comment
         d1.feed({'message'=> 'b' * 100})
         d1.feed({'message'=> 'c' * 100})
       end
+      d1.instance.flush_emit(60)
     end
-    out = capture_log(d1.instance.log) { d1.instance.flush_emit(60) }
-    assert { out.include?("comment:foobar") }
+    assert_equal(["plugin:out_flowcounter_simple\tcount:3\tindicator:num\tunit:second\tcomment:foobar\n"],
+                 normalize_logs(d1.logs))
   end
 end