Merge pull request #1077 from okkez/add-feature-to-get-filtered-records

Add feature to get filtered records to Fluent::Test::Driver::Filter

lib/fluent/test/driver/filter.rb

@@ -25,9 +25,31 @@ module Driver
       class Filter < Base
         include EventFeeder
 
+        attr_reader :filtered
+
         def initialize(klass, opts: {}, &block)
           super
           raise ArgumentError, "plugin is not an instance of Fluent::Plugin::Filter" unless @instance.is_a? Fluent::Plugin::Filter
+          @filtered = []
+        end
+
+        def filtered_records
+          @filtered.map {|_time, record| record }
+        end
+
+        def instance_hook_after_started
+          super
+          filter_hook = ->(time, record) { @filtered << [time, record] }
+          m = Module.new do
+            define_method(:filter_stream) do |tag, es|
+              new_es = super(tag, es)
+              new_es.each do |time, record|
+                filter_hook.call(time, record)
+              end
+              new_es
+            end
+          end
+          @instance.singleton_class.prepend(m)
         end
       end
     end