diff --git a/test/support/protocol_test_case.rb b/test/support/protocol_test_case.rb
index 4970742a4..057ddb8f1 100644
--- a/test/support/protocol_test_case.rb
+++ b/test/support/protocol_test_case.rb
@@ -282,7 +282,10 @@ def assert_watch_result expected,  expression, frame_idx: 0
     def execute_dap_scenario scenario
       ENV['RUBY_DEBUG_TEST_UI'] = 'vscode'
 
-      @remote_info = setup_unix_domain_socket_remote_debuggee
+      # TestInfo is defined to use kill_remote_debuggee method.
+      test_info = TestInfo.new
+
+      @remote_info = test_info.remote_info = setup_unix_domain_socket_remote_debuggee
       Timeout.timeout(TIMEOUT_SEC) do
         sleep 0.001 until @remote_info.debuggee_backlog.join.include? 'connection...'
       end
@@ -294,21 +297,23 @@ def execute_dap_scenario scenario
 
       attach_to_dap_server
       scenario.call
-
-      flunk create_protocol_message "Expected the debuggee program to finish" unless wait_pid @remote_info.pid, TIMEOUT_SEC
     ensure
       @reader_thread&.kill
       @sock&.close
-      @remote_info&.reader_thread&.kill
-      @remote_info&.r&.close
-      @remote_info&.w&.close
+      kill_remote_debuggee test_info
+      if name = test_info.failed_process
+        flunk create_protocol_message "Expected the debuggee program to finish"
+      end
     end
 
     def execute_cdp_scenario_ scenario
       ENV['RUBY_DEBUG_TEST_UI'] = 'chrome'
 
+      # TestInfo is defined to use kill_remote_debuggee method.
+      test_info = TestInfo.new
+
       @web_sock = nil
-      @remote_info = setup_tcpip_remote_debuggee
+      @remote_info = test_info.remote_info = setup_tcpip_remote_debuggee
       Timeout.timeout(TIMEOUT_SEC) do
         sleep 0.001 until @remote_info.debuggee_backlog.join.include? @remote_info.port.to_s
       end
@@ -320,14 +325,13 @@ def execute_cdp_scenario_ scenario
 
       attach_to_cdp_server
       scenario.call
-
-      flunk create_protocol_message "Expected the debuggee program to finish" unless wait_pid @remote_info.pid, TIMEOUT_SEC
     ensure
       @reader_thread&.kill
       @web_sock&.close
-      @remote_info&.reader_thread&.kill
-      @remote_info&.r&.close
-      @remote_info&.w&.close
+      kill_remote_debuggee test_info
+      if name = test_info.failed_process
+        flunk create_protocol_message "Expected the debuggee program to finish"
+      end
     end
 
     def execute_cdp_scenario scenario
diff --git a/test/support/protocol_test_case_test.rb b/test/support/protocol_test_case_test.rb
new file mode 100644
index 000000000..2f9e494e3
--- /dev/null
+++ b/test/support/protocol_test_case_test.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+# FIXME: this test doesn't pass
+
+# require_relative 'protocol_test_case'
+
+# module DEBUGGER__
+#   class TestFrameworkTestHOge < ProtocolTestCase
+#     PROGRAM = <<~RUBY
+#       1| a=1
+#     RUBY
+
+#     def test_the_test_fails_when_debuggee_doesnt_exit
+#       assert_fail_assertion do
+#         run_protocol_scenario PROGRAM do
+#         end
+#       end
+#     end
+#   end
+# end