add TIME type conversion to string converter

Author: p-eye

lib/embulk/output/bigquery/value_converter_factory.rb

@@ -224,6 +224,13 @@ def string_converter
                 val # Users must care of BQ timestamp format
               }
             end
+          when 'TIME'
+            Proc.new {|val|
+              next nil if val.nil?
+              with_typecast_error(val) do |val|
+                Time.parse(val).strftime("%H:%M:%S.%6N")
+              end
+            }
           when 'RECORD'
             Proc.new {|val|
               next nil if val.nil?

test/test_value_converter_factory.rb

@@ -262,6 +262,15 @@ def test_datetime
           assert_equal "2016-02-26 00:00:00", converter.call("2016-02-26 00:00:00")
         end
 
+        def test_time
+          converter = ValueConverterFactory.new(
+            SCHEMA_TYPE, 'TIME',
+            timestamp_format: '%H:%M:%S'
+          ).create_converter
+          assert_equal nil, converter.call(nil)
+          assert_equal "00:03:22.000000", converter.call("00:03:22")
+        end
+
         def test_record
           converter = ValueConverterFactory.new(SCHEMA_TYPE, 'RECORD').create_converter
           assert_equal({'foo'=>'foo'}, converter.call(%Q[{"foo":"foo"}]))