How to mock Logger in Rails test using Test::Unit?

Question

In test_helper:

class Logger
    @@log = []

  def self.info(message)
    @@log.push(message)
  end

  def self.log
    @@log
  end
end

But when running the tests it seems to use the regular Logger.

How to create a mock for the Logger?

Rails 3.0.7.

Answer 1

You need to assign your logger to the Rails.logger for Rails to use it... For you to fully implement logger, you need to implement all of the methods http://www.ruby-doc.org/stdlib-1.9.3/libdoc/logger/rdoc/Logger.html (namely #debug, #warn, #error, #fatal)

ENV["RAILS_ENV"] = "test"
require File.expand_path(File.dirname(__FILE__) + "/../config/environment")

class Logger
    @@log = []

  def self.info(message)
    @@log.push(message)
  end 

  def self.log
    @@log
  end 
end


class TestLogCase < ActiveSupport::TestCase
  def setup
    Rails.logger = Logger
  end 

  test "records the log" do
    Rails.logger.info "My Message"
    assert_true Logger.log.include?("My Message")
  end                                                                                                                         
end