1 files changed, 114 insertions, 0 deletions
diff --git a/activerecord/test/cases/connection_management_test.rb b/activerecord/test/cases/connection_management_test.rb
new file mode 100644
index 0000000000..0941ee3309
--- /dev/null
+++ b/activerecord/test/cases/connection_management_test.rb
@@ -0,0 +1,114 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "rack"
+
+module ActiveRecord
+  module ConnectionAdapters
+    class ConnectionManagementTest < ActiveRecord::TestCase
+      self.use_transactional_tests = false
+
+      class App
+        attr_reader :calls
+        def initialize
+          @calls = []
+        end
+
+        def call(env)
+          @calls << env
+          [200, {}, ["hi mom"]]
+        end
+      end
+
+      def setup
+        @env = {}
+        @app = App.new
+        @management = middleware(@app)
+
+        # make sure we have an active connection
+        assert ActiveRecord::Base.connection
+        assert_predicate ActiveRecord::Base.connection_handler, :active_connections?
+      end
+
+      def test_app_delegation
+        manager = middleware(@app)
+
+        manager.call @env
+        assert_equal [@env], @app.calls
+      end
+
+      def test_body_responds_to_each
+        _, _, body = @management.call(@env)
+        bits = []
+        body.each { |bit| bits << bit }
+        assert_equal ["hi mom"], bits
+      end
+
+      def test_connections_are_cleared_after_body_close
+        _, _, body = @management.call(@env)
+        body.close
+        assert_not_predicate ActiveRecord::Base.connection_handler, :active_connections?
+      end
+
+      def test_active_connections_are_not_cleared_on_body_close_during_transaction
+        ActiveRecord::Base.transaction do
+          _, _, body = @management.call(@env)
+          body.close
+          assert_predicate ActiveRecord::Base.connection_handler, :active_connections?
+        end
+      end
+
+      def test_connections_closed_if_exception
+        app       = Class.new(App) { def call(env); raise NotImplementedError; end }.new
+        explosive = middleware(app)
+        assert_raises(NotImplementedError) { explosive.call(@env) }
+        assert_not_predicate ActiveRecord::Base.connection_handler, :active_connections?
+      end
+
+      def test_connections_not_closed_if_exception_inside_transaction
+        ActiveRecord::Base.transaction do
+          app               = Class.new(App) { def call(env); raise RuntimeError; end }.new
+          explosive         = middleware(app)
+          assert_raises(RuntimeError) { explosive.call(@env) }
+          assert_predicate ActiveRecord::Base.connection_handler, :active_connections?
+        end
+      end
+
+      test "doesn't clear active connections when running in a test case" do
+        executor.wrap do
+          @management.call(@env)
+          assert_predicate ActiveRecord::Base.connection_handler, :active_connections?
+        end
+      end
+
+      test "proxy is polite to its body and responds to it" do
+        body = Class.new(String) { def to_path; "/path"; end }.new
+        app = lambda { |_| [200, {}, body] }
+        response_body = middleware(app).call(@env)[2]
+        assert_respond_to response_body, :to_path
+        assert_equal "/path", response_body.to_path
+      end
+
+      test "doesn't mutate the original response" do
+        original_response = [200, {}, "hi"]
+        app = lambda { |_| original_response }
+        middleware(app).call(@env)[2]
+        assert_equal "hi", original_response.last
+      end
+
+      private
+        def executor
+          @executor ||= Class.new(ActiveSupport::Executor).tap do |exe|
+            ActiveRecord::QueryCache.install_executor_hooks(exe)
+          end
+        end
+
+        def middleware(app)
+          lambda do |env|
+            a, b, c = executor.wrap { app.call(env) }
+            [a, b, Rack::BodyProxy.new(c) {}]
+          end
+        end
+    end
+  end
+end