Because engines can contain functionality that is a part of an

application in a strong sense, we sometimes want to run tests for
those engines as part of the application test suite.

The new test:engines:* tasks will only run tests from 'engine'
plugins (those containing an 'app' directory), as running tests
for all plugins can often interact badly with the application
tests (i.e. the often expect to be run independently, with their
own schema, etc, or in even more esoteric ways, like the tests
in the engines plugin itself).

We should be able to test that these tests can be overridable.

Clean up fixtures created by test:engines:all

Rakefile

@@ -182,6 +182,8 @@ namespace :test do
 
     insert_line("require 'engines_test_helper'", :into => 'test/test_helper.rb')
 
+    insert_line("task :test => ['test:engines:all']", :into => 'Rakefile')
+
     puts "> Mirroring test application files into #{test_app_dir}"
     mirror_test_files('app')
     mirror_test_files('lib')

tasks/engines.rake

@@ -217,6 +217,34 @@ Report any issues on http://dev.rails-engines.org. Thanks!
 -~===============( ... as you were ... )============================~-}
   end
 
+  namespace :engines do
+
+    def engine_plugins
+      Dir["vendor/plugins/*"].select { |f| File.directory?(File.join(f, "app")) }.map { |f| File.basename(f) }.join(",")
+    end
+
+    desc "Run tests from within engines plugins (plugins with an 'app' directory)"
+    task :all => [:units, :functionals, :integration]
+
+    desc "Run unit tests from within engines plugins (plugins with an 'app' directory)"
+    Rake::TestTask.new(:units => "test:plugins:setup_plugin_fixtures") do |t|
+      t.pattern = "vendor/plugins/{#{ENV['PLUGIN'] || engine_plugins}}/test/unit/**/*_test.rb"
+      t.verbose = true
+    end
+
+    desc "Run functional tests from within engines plugins (plugins with an 'app' directory)"
+    Rake::TestTask.new(:functionals => "test:plugins:setup_plugin_fixtures") do |t|
+      t.pattern = "vendor/plugins/{#{ENV['PLUGIN'] || engine_plugins}}/test/functional/**/*_test.rb"
+      t.verbose = true
+    end
+
+    desc "Run integration tests from within engines plugins (plugins with an 'app' directory)"
+    Rake::TestTask.new(:integration => "test:plugins:setup_plugin_fixtures") do |t|
+      t.pattern = "vendor/plugins/{#{ENV['PLUGIN'] || engine_plugins}}/test/integration/**/*_test.rb"
+      t.verbose = true
+    end
+  end
+
   namespace :plugins do
 
     desc "Run the plugin tests in vendor/plugins/**/test (or specify with PLUGIN=name)"

test/plugins/test_testing/test/unit/override_test.rb

@@ -0,0 +1,13 @@
+require File.expand_path(File.join(File.dirname(__FILE__), *%w[.. .. .. .. .. test test_helper]))
+
+class OverrideTest < ActiveSupport::TestCase
+  def test_overrides_from_the_application_should_work
+    flunk "this test should be overridden by the app"
+  end
+
+  def test_tests_within_the_plugin_should_still_run
+    assert true, "non-overridden plugin tests should still run"
+  end
+end
+
+Engines::Testing.override_tests_from_app

test/unit/test_testing/override_test.rb

@@ -0,0 +1,7 @@
+require File.join(File.dirname(__FILE__), *%w[.. .. test_helper])
+
+class OverrideTest < ActiveSupport::TestCase
+  def test_overrides_from_the_application_should_work
+    assert true, "overriding plugin tests from the application should work"
+  end
+end

test/unit/testing_test.rb

@@ -4,9 +4,10 @@ class TestingTest < Test::Unit::TestCase
   def setup
     Engines::Testing.set_fixture_path
     @filename = File.join(Engines::Testing.temporary_fixtures_directory, 'testing_fixtures.yml')
+    File.delete(@filename) if File.exists?(@filename)
   end
 
-  def teardown    
+  def teardown
     File.delete(@filename) if File.exists?(@filename)
   end