diff --git a/railties/lib/rails/test_unit/runner.rb b/railties/lib/rails/test_unit/runner.rb
index 45e8472f6a..de5744c662 100644
--- a/railties/lib/rails/test_unit/runner.rb
+++ b/railties/lib/rails/test_unit/runner.rb
@@ -12,11 +12,8 @@ module Rails
 
       class << self
         def attach_before_load_options(opts)
-          ENV["RAILS_ENV"] = "test"
           opts.on("--warnings", "-w", "Run with Ruby warnings enabled") {}
-          opts.on("-e", "--environment ENV", "Run tests in the ENV environment") { |e|
-            ENV["RAILS_ENV"] = e
-          }
+          opts.on("-e", "--environment ENV", "Run tests in the ENV environment") {}
         end
 
         def parse_options(argv)
diff --git a/railties/test/application/test_runner_test.rb b/railties/test/application/test_runner_test.rb
index 17333b6ac9..a01325fdb8 100644
--- a/railties/test/application/test_runner_test.rb
+++ b/railties/test/application/test_runner_test.rb
@@ -593,7 +593,7 @@ module ApplicationTests
 
       file = create_test_for_env("development")
       results = Dir.chdir(app_path) {
-        `ruby -Ilib:test #{file} -e development`.each_line.map { |line| JSON.parse line }
+        `RAILS_ENV=development ruby -Ilib:test #{file}`.each_line.map { |line| JSON.parse line }
       }
       assert_equal 1, results.length
       failures = results.first["failures"]