diff --git a/lib/ruby_lsp/ruby_lsp_rails/runner_client.rb b/lib/ruby_lsp/ruby_lsp_rails/runner_client.rb
index 5c52b7b5..642eeb25 100644
--- a/lib/ruby_lsp/ruby_lsp_rails/runner_client.rb
+++ b/lib/ruby_lsp/ruby_lsp_rails/runner_client.rb
@@ -170,7 +170,7 @@ def make_request(request, params = nil)
         read_response
       end
 
-      sig { params(request: String, params: T.nilable(T::Hash[Symbol, T.untyped])).void }
+      sig { overridable.params(request: String, params: T.nilable(T::Hash[Symbol, T.untyped])).void }
       def send_message(request, params = nil)
         message = { method: request }
         message[:params] = params if params
@@ -181,9 +181,11 @@ def send_message(request, params = nil)
         # The server connection died
       end
 
-      alias_method :send_notification, :send_message
+      # Notifications are like messages, but one-way, with no response sent back.
+      sig { params(request: String, params: T.nilable(T::Hash[Symbol, T.untyped])).void }
+      def send_notification(request, params = nil) = send_message(request, params)
 
-      sig { returns(T.nilable(T::Hash[Symbol, T.untyped])) }
+      sig { overridable.returns(T.nilable(T::Hash[Symbol, T.untyped])) }
       def read_response
         headers = @stdout.gets("\r\n\r\n")
         raise IncompleteMessageError unless headers
diff --git a/test/ruby_lsp_rails/runner_client_test.rb b/test/ruby_lsp_rails/runner_client_test.rb
index 3fd910b6..9ffdf5cb 100644
--- a/test/ruby_lsp_rails/runner_client_test.rb
+++ b/test/ruby_lsp_rails/runner_client_test.rb
@@ -87,5 +87,33 @@ class RunnerClientTest < ActiveSupport::TestCase
         FileUtils.mv("test/dummy/config/application.rb.bak", "test/dummy/config/application.rb")
       end
     end
+
+    class NullClientTest < ActiveSupport::TestCase
+      setup { @client = NullClient.new }
+
+      test "#shutdown is a no-op" do
+        assert_nothing_raised { @client.shutdown }
+      end
+
+      test "#stopped? is always true" do
+        assert_predicate @client, :stopped?
+      end
+
+      test "#rails_root is just the current working directory" do
+        assert_equal Dir.pwd, @client.rails_root
+      end
+
+      test "#send_message is a no-op" do
+        assert_nothing_raised { @client.send(:send_message, "request", nil) }
+      end
+
+      test "#send_notification is a no-op" do
+        assert_nothing_raised { @client.send(:send_notification, "request", nil) }
+      end
+
+      test "#read_response is a no-op" do
+        assert_nothing_raised { @client.send(:read_response) }
+      end
+    end
   end
 end