test: don't use deprecated way of capturing logs

`capture_log` is for older versions as well as the following.

https://github.com/fluent/fluentd/blob/6c649d189b5cf65ccfce58f6952a31b24c775e72/lib/fluent/test/helpers.rb#L110-L122

We should use `Driver::logs` instead.

In addition, this fixes the following points.

* Update `helper.rb` since it was updated very long ago and there
  are some unnecessary codes.
* Assert the entire log message (without the timestamp and the
  log level), since this is easier to see the diff of the expected
  and the actual when the assertion fails.

Signed-off-by: Daijiro Fukuda <[email protected]>

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

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

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