Agile Web Development

This plugin adds a couple of class methods to Test::Unit::TestCase to make it easy to use share helper methods between test cases in modules.

A typical Rails project has the following test directory structure:

  test/         # the root test directory
    fixtures/   # fixtures used while testing
    functional/ # functional tests
    unit/       # unit tests

The test_helpers Rails plugin adds an additional directory:

  test/
    helpers/

Drop modules in the "test/helpers" that contain code that you would like to share between test cases. For example. Suppose you created a couple of custom assertions that you would like to use in your test cases. You could create a custom module (MyAssertionsTestHelper) and drop it in the "test/helpers" directory like this:

  module MyAssertionsTestHelper

    def assert_this(expected, result)
      # implementation
    end

    def assert_that(expected, result)
      # impementation
    end

  end

Be sure that both the module name and filename end with "TestHelper" (so for the module above the filename should be "my_assertions_test_helper.rb").

Now, in a test case where you would like to use the test helper simply invoke the "test_helper" class method:

  class MyTest < Test::Unit::TestCase

    test_helper :my_assertions

    def test_custom_assertion
      assert_this(123, 456)
      assert_that("abc", "def")
    end

  end

The "test_helper" class method takes an array of symbols and automatically loads and includes the appropriate modules. In the example above it examines the :my_assertions symbol and concludes that you want to require "test/helper/my_assertions_test_helper" and include MyAssertionsTestHelper into your test case.

If you would like to modify the test helper load path you can do so with the "test_helper_paths" class method:

  class Test::Unit::TestCase
    self.test_helper_paths << '/custom/helper/path'
  end

The test helper plugin is Copyright © John W. Long, 2007 and is available under the same license as Rails.

Owner: John W. Long

Home: http://wiseheartdesign.com/2007/5/3/two-rails-testing-plugins

Repository: http://wiseheartdesign.com/svn/plugins/test_helpers/

License: Rails' (MIT)

Category: Testing