Module: Engines::Testing

Defined in:
lib/engines/testing.rb

Overview

In most cases, Rails’ own plugin testing mechanisms are sufficient. However, there are cases where plugins can be given a helping hand in the testing arena. This module contains some methods to assist when testing plugins that contain fixtures.

Fixtures and plugins

Since Rails’ own fixtures method is fairly strict about where files can be loaded from, the simplest approach when running plugin tests with fixtures is to simply copy all fixtures into a single temporary location and inform the standard Rails mechanism to use this directory, rather than RAILS_ROOT/test/fixtures.

The Engines::Testing#setup_plugin_fixtures method does this, copying all plugin fixtures into the temporary location before and tests are performed. This behaviour is invoked the the rake tasks provided by the Engines plugin, in the “test:plugins” namespace. If necessary, you can invoke the task manually.

If you wish to take advantage of this, add a call to the Engines::Testing.set_fixture_path method somewhere before your tests (in a test_helper file, or above the TestCase itself).

Testing plugins

Normally testing a plugin will require that Rails is loaded, unless you are including a skeleton Rails environment or set of mocks within your plugin tests. If you require the Rails environment to be started, you must ensure that this actually happens; while it’s not obvious, your tests do not automatically run with Rails loaded.

The simplest way to setup plugin tests is to include a test helper with the following contents:

# Load the normal Rails helper. This ensures the environment is loaded
require File.expand_path(File.dirname(__FILE__) + '/../../../../test/test_helper')
# Ensure that we are using the temporary fixture path
Engines::Testing.set_fixture_path

Then run tests using the provided tasks (test:plugins, or the tasks that the engines plugin provides - test:plugins:units, etc.).

Alternatively, you can explicitly load the environment by adpating the contents of the default test_helper:

ENV["RAILS_ENV"] = "test"
# Note that we are requiring config/environment from the root of the enclosing application.
require File.expand_path(File.dirname(__FILE__) + "/../../../../config/environment")
require 'test_help'

Class Method Summary collapse

Class Method Details

.set_fixture_path ⇒ Object

Sets the fixture path used by Test::Unit::TestCase to the temporary directory which contains all plugin fixtures.



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# File 'lib/engines/testing.rb', line 83

def self.set_fixture_path
  Test::Unit::TestCase.fixture_path = self.temporary_fixtures_directory
  $LOAD_PATH.unshift self.temporary_fixtures_directory
end

.setup_plugin_fixtures(plugins = Engines.plugins.by_precedence) ⇒ Object

Copies fixtures from plugins and the application into a temporary directory (Engines::Testing.temporary_fixtures_directory).

If a set of plugins is not given, fixtures are copied from all plugins in order of precedence, meaning that plugins can ‘overwrite’ the fixtures of others if they are loaded later; the application’s fixtures are copied last, allowing any custom fixtures to override those in the plugins. If no argument is given, plugins are loaded via PluginList#by_precedence.

This method is called by the engines-supplied plugin testing rake tasks



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# File 'lib/engines/testing.rb', line 68

def self.setup_plugin_fixtures(plugins = Engines.plugins.by_precedence)
  
  # Copy all plugin fixtures, and then the application fixtures, into this directory
  plugins.each do |plugin| 
    plugin_fixtures_directory =  File.join(plugin.directory, "test", "fixtures")
    if File.directory?(plugin_fixtures_directory)
      Engines.mirror_files_from(plugin_fixtures_directory, self.temporary_fixtures_directory)
    end
  end
  Engines.mirror_files_from(File.join(RAILS_ROOT, "test", "fixtures"),
                            self.temporary_fixtures_directory)
end