Make it possible to fail fast in isolated run

lib/ttnt/testtask.rb

@@ -75,6 +75,7 @@ def define_run_task
             tests.each do |test|
               args = "#{@rake_testtask.ruby_opts_string} #{test} #{@rake_testtask.option_list}"
               run_ruby args
+              break if @failed && ENV['FAIL_FAST']
             end
           else
             args =
@@ -117,6 +118,7 @@ def define_anchor_task
     # @param args [String] argument to pass to ruby
     def run_ruby(args)
       ruby "#{args}" do |ok, status|
+        @failed = true if !ok
         if !ok && status.respond_to?(:signaled?) && status.signaled?
           raise SignalException.new(status.termsig)
         end

test/integration_test.rb

@@ -53,6 +53,18 @@ def test_isolated
         ENV.delete('ISOLATED')
         assert_equal 3, output[:stdout].split('# Running:').count
       end
+
+      def test_isolated_with_fail_fast
+        @repo.checkout('change_fizz')
+        fizzbuzz_file = "#{@repo.workdir}/fizzbuzz.rb"
+        File.write(fizzbuzz_file, File.read(fizzbuzz_file).gsub(/"buzz"$/, '"bar"'))
+        ENV['ISOLATED'] = '1'
+        ENV['FAIL_FAST'] = '1'
+        output = rake('ttnt:test:run')
+        ENV.delete('ISOLATED')
+        ENV.delete('FAIL_FAST')
+        assert_equal 2, output[:stdout].split('Failure:').count
+      end
     end
 
     class AdditionAmongComments < TTNT::TestCase::AdditionAmongComments