prevent rake test to run the test suite three times when ENV['TEST'] is set [#3572 state:resolved]

Signed-off-by: Xavier Noria <fxn@hashref.com>

actionpack/RUNNING_UNIT_TESTS

@@ -8,15 +8,18 @@ Rake can be found at http://rake.rubyforge.org
 
 == Running by hand
 
-If you only want to run a single test suite, or don't want to bother with Rake,
-you can do so with something like:
+To run a single test suite
 
-   ruby -Itest test/controller/base_tests.rb
+   rake test TEST=path/to/test.rb
 
-== Dependency on ActiveRecord and database setup
+which can be further narrowed down to one test:
+
+   rake test TEST=path/to/test.rb TESTOPTS="--name=test_something"
+
+== Dependency on Active Record and database setup
 
 Test cases in the test/controller/active_record/ directory depend on having
-activerecord and sqlite installed. If ActiveRecord is not in
+activerecord and sqlite installed. If Active Record is not in
 actionpack/../activerecord directory, or the sqlite rubygem is not installed,
 these tests are skipped.
 

railties/lib/rails/test_unit/testing.rake

@@ -73,7 +73,8 @@ end
 
 desc 'Runs test:units, test:functionals, test:integration together (also available: test:benchmark, test:profile, test:plugins)'
 task :test do
-  errors = %w(test:units test:functionals test:integration).collect do |task|
+  tests_to_run = ENV['TEST'] ? ["test:single"] : %w(test:units test:functionals test:integration)
+  errors = tests_to_run.collect do |task|
     begin
       Rake::Task[task].invoke
       nil
@@ -123,6 +124,10 @@ namespace :test do
   end
   Rake::Task['test:uncommitted'].comment = "Test changes since last checkin (only Subversion and Git)"
 
+  Rake::TestTask.new(:single => "test:prepare") do |t|
+    t.libs << "test"
+  end
+
   TestTaskWithoutDescription.new(:units => "test:prepare") do |t|
     t.libs << "test"
     t.pattern = 'test/unit/**/*_test.rb'