Add process extenstion to use Procss.clock_gettime with timecop

Signed-off-by: Yuta Iwama <[email protected]>

test/helper.rb

@@ -50,6 +50,7 @@ def to_masked_element
 require 'fluent/time'
 require 'serverengine'
 require 'helpers/fuzzy_assert'
+require 'helpers/process_extenstion'
 
 module Fluent
   module Plugin

test/helpers/process_extenstion.rb

@@ -0,0 +1,32 @@
+require 'timecop'
+
+module Process
+  class << self
+    # this can be used with timecop
+    def clock_gettime(clock_id, unit = :float_second)
+      if Process::CLOCK_REALTIME
+        t = Time.now
+
+        case unit
+        when :float_second
+          t.to_i + t.nsec / 1_000_000_000.0
+        when :float_millisecond
+          t.to_i * 1_000 + t.nsec / 1_000_000.0
+        when :float_microsecond
+          t.to_i * 1_000_000 + t.nsec / 1_000.0
+        when :second
+          t.to_i
+        when :millisecond
+          t.to_i * 1000 + t.nsec / 1_000_000
+        when :microsecond
+          t.to_i * 1_000_000 + t.nsec / 1_000
+        when :nanosecond
+          t.to_i * 1_000_000_000 + t.nsec
+        end
+      else
+        # TODO
+        super
+      end
+    end
+  end
+end