1 files changed, 18 insertions, 1 deletions
diff --git a/actionpack/test/dispatch/system_testing/server_test.rb b/actionpack/test/dispatch/system_testing/server_test.rb
index 1866225fc1..95e411faf4 100644
--- a/actionpack/test/dispatch/system_testing/server_test.rb
+++ b/actionpack/test/dispatch/system_testing/server_test.rb
@@ -6,10 +6,27 @@ require "action_dispatch/system_testing/server"
 
 class ServerTest < ActiveSupport::TestCase
   setup do
-    ActionDispatch::SystemTesting::Server.new.run
+    @old_capybara_server = Capybara.server
   end
 
   test "port is always included" do
+    ActionDispatch::SystemTesting::Server.new.run
     assert Capybara.always_include_port, "expected Capybara.always_include_port to be true"
   end
+
+  test "server is changed from `default` to `puma`" do
+    Capybara.server = :default
+    ActionDispatch::SystemTesting::Server.new.run
+    refute_equal Capybara.server, Capybara.servers[:default]
+  end
+
+  test "server is not changed to `puma` when is different than default" do
+    Capybara.server = :webrick
+    ActionDispatch::SystemTesting::Server.new.run
+    assert_equal Capybara.server, Capybara.servers[:webrick]
+  end
+
+  teardown do
+    Capybara.server = @old_capybara_server
+  end
 end