added a test suite for the postgres binary type

this shows a problem with nil values

activerecord/test/cases/adapters/postgresql/bytea_test.rb

+# encoding: utf-8
+
+require "cases/helper"
+require 'active_record/base'
+require 'active_record/connection_adapters/postgresql_adapter'
+
+class PostgresqlByteaTest < ActiveRecord::TestCase
+  class ByteaDataType < ActiveRecord::Base
+    self.table_name = 'bytea_data_type'
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    begin
+      @connection.transaction do
+        @connection.create_table('bytea_data_type') do |t|
+          t.binary 'payload'
+        end
+      end
+    end
+    @column = ByteaDataType.columns.find { |c| c.name == 'payload' }
+    assert(@column.is_a?(ActiveRecord::ConnectionAdapters::PostgreSQLColumn))
+  end
+
+  def teardown
+    @connection.execute 'drop table if exists bytea_data_type'
+  end
+
+  def test_column
+    assert_equal :binary, @column.type
+  end
+
+  def test_type_cast_binary_converts_the_encoding
+    assert @column
+
+    data = "\u001F\x8B"
+    assert_equal('UTF-8', data.encoding.name)
+    assert_equal('ASCII-8BIT', @column.type_cast(data).encoding.name)
+  end
+
+  def test_type_cast_binary_value
+    data = "\u001F\x8B".force_encoding("BINARY")
+    assert_equal(data, @column.type_cast(data))
+  end
+
+  def test_type_case_nil
+    assert_equal(nil, @column.type_cast(nil))
+  end
+
+  def test_read_value
+    data = "\u001F"
+    @connection.execute "insert into bytea_data_type (payload) VALUES ('#{data}')"
+    record = ByteaDataType.first
+    assert_equal(data, record.payload)
+    record.delete
+  end
+
+  def test_read_nil_value
+    @connection.execute "insert into bytea_data_type (payload) VALUES (null)"
+    record = ByteaDataType.first
+    assert_equal(nil, record.payload)
+    record.delete
+  end
+
+  def test_write_value
+    data = "\u001F"
+    record = ByteaDataType.create(payload: data)
+    refute record.new_record?
+    assert_equal(data, record.payload)
+  end
+
+  def test_write_file
+    data = File.read(File.join(File.dirname(__FILE__), '..', '..', '..', 'assets', 'example.log'))
+    assert(data.size > 1)
+    record = ByteaDataType.create(payload: data)
+    refute record.new_record?
+    assert_equal(data, record.payload)
+    assert_equal(data, ByteaDataType.where(id: record.id).first.payload)
+  end
+
+  def test_write_nil
+    record = ByteaDataType.create(payload: nil)
+    refute record.new_record?
+    assert_equal(nil, record.payload)
+    assert_equal(nil, ByteaDataType.where(id: record.id).first.payload)
+  end
+end