ar/connection_pool: honor overriden rack.test in middleware

Honoring an overidden `rack.test` allows testing closed connection between
multiple requests. This is useful if you're working on database resiliency, to
ensure the connection is in the expected state from one request to another on
the same worker.

3 files changed, 14 insertions, 1 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index f195b73437..147599d5c3 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,8 @@
+*   Honor overridden `rack.test` in Rack environment for the connection
+    management middlware.
+
+    *Simon Eskildsen*
+
 *   Add a truncate method to the connection.
 
     *Aaron Patterson*
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
index bc1a670b42..9760729da3 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
@@ -640,7 +640,7 @@ module ActiveRecord
       end
 
       def call(env)
-        testing = env.key?('rack.test')
+        testing = env['rack.test']
 
         response = @app.call(env)
         response[2] = ::Rack::BodyProxy.new(response[2]) do
diff --git a/activerecord/test/cases/connection_management_test.rb b/activerecord/test/cases/connection_management_test.rb
index 77d9ae9b8e..f53c496ecd 100644
--- a/activerecord/test/cases/connection_management_test.rb
+++ b/activerecord/test/cases/connection_management_test.rb
@@ -96,6 +96,14 @@ module ActiveRecord
         assert ActiveRecord::Base.connection_handler.active_connections?
       end
 
+      def test_connections_closed_if_exception_and_explicitly_not_test
+        @env['rack.test'] = false
+        app       = Class.new(App) { def call(env); raise NotImplementedError; end }.new
+        explosive = ConnectionManagement.new(app)
+        assert_raises(NotImplementedError) { explosive.call(@env) }
+        assert !ActiveRecord::Base.connection_handler.active_connections?
+      end
+
       test "doesn't clear active connections when running in a test case" do
         @env['rack.test'] = true
         @management.call(@env)