module Rails::Generators::Testing::Assertions

end
end
assert_match(/Product\.all/, index)
assert_instance_method :index, controller do |index|
assert_file "app/controllers/products_controller.rb" do |controller|

Finally, when a block is given, it yields the file content:

assert_file "config/environment.rb", /initialize/

file with the given string:
regular expression matches the given file content. If it's a string, it compares the
You can also give extra arguments. If the argument is a regexp, it will check if the

assert_file "config/environment.rb"

to the configured destination:
Asserts a given file exists. You need to supply an absolute path or a path relative

def assert_file(relative, *contents)
  absolute = File.expand_path(relative, destination_root)
  assert File.exist?(absolute), "Expected file #{relative.inspect} to exist, but does not"
  read = File.read(absolute) if block_given? || !contents.empty?
  assert_nothing_raised { yield read } if block_given?
  contents.each do |content|
    case content
    when String
      assert_equal content, read
    when Regexp
      assert_match content, read
    end
  end
end