1 files changed, 10 insertions, 0 deletions
diff --git a/railties/test/test_unit/runner_test.rb b/railties/test/test_unit/runner_test.rb
index fa5442c15c..c040c71635 100644
--- a/railties/test/test_unit/runner_test.rb
+++ b/railties/test/test_unit/runner_test.rb
@@ -1,7 +1,10 @@
 require 'abstract_unit'
+require 'env_helpers'
 require 'rails/test_unit/runner'
 
 class TestUnitTestRunnerTest < ActiveSupport::TestCase
+  include EnvHelpers
+
   setup do
     @options = Rails::TestRunner::Options
   end
@@ -19,6 +22,13 @@ class TestUnitTestRunnerTest < ActiveSupport::TestCase
     assert options[:backtrace]
   end
 
+  test "show full backtrace using BACKTRACE environment variable" do
+    switch_env "BACKTRACE", "true" do
+      options = @options.parse([])
+      assert options[:backtrace]
+    end
+  end
+
   test "tests run in the test environment by default" do
     options = @options.parse([])
     assert_equal "test", options[:environment]