diff --git a/railties/lib/rails/test_unit/testing.rake b/railties/lib/rails/test_unit/testing.rake
index 8bcceb9b2c..52d92cdd96 100644
--- a/railties/lib/rails/test_unit/testing.rake
+++ b/railties/lib/rails/test_unit/testing.rake
@@ -121,16 +121,9 @@ namespace :test do
       models      = changed_since_checkin.select { |path| path =~ /app[\\\/]models[\\\/].*\.rb$/ }
       controllers = changed_since_checkin.select { |path| path =~ /app[\\\/]controllers[\\\/].*\.rb$/ }
 
-      unit_tests = models.map do |model|
-        file = "test/unit/#{File.basename(model, '.rb')}_test.rb"
-        file if File.exist?(file)
-      end
-      functional_tests = controllers.map do |controller|
-        file = "test/functional/#{File.basename(controller, '.rb')}_test.rb"
-        file if File.exist?(file)
-      end
-
-      (unit_tests.uniq + functional_tests.uniq).compact
+      unit_tests       = models.map { |model| "test/unit/#{File.basename(model, '.rb')}_test.rb" }
+      functional_tests = controllers.map { |controller| "test/functional/#{File.basename(controller, '.rb')}_test.rb" }
+      (unit_tests + functional_tests).uniq.select { |file| File.exist?(file) }
     end
 
     t.libs << 'test'