DEBUG

lib/ruby_lsp/ruby_lsp_rails/runner_client.rb

@@ -290,7 +290,7 @@ def read_response
             break if content_length.nonzero?
 
             failed_headers << headers
-            log_message(
+            $stderr.puts(
               "Ruby LSP Rails expected message headers but got: #{headers}. Trying again...",
               type: Constant::MessageType::WARNING,
             )
@@ -305,7 +305,7 @@ def read_response
               #{failed_headers.join("\n")}
             MESSAGE
 
-            log_message(message, type: Constant::MessageType::WARNING)
+            $stderr.puts(message, type: Constant::MessageType::WARNING)
             return
           end
 

test/ruby_lsp_rails/launch_test.rb

@@ -0,0 +1,27 @@
+# typed: true
+# frozen_string_literal: true
+
+require "test_helper"
+
+module RubyLsp
+  module Rails
+    class LaunchTest < ActiveSupport::TestCase
+      test "launching the client succeeds" do
+        outgoing_queue = Thread::Queue.new
+
+        client = RunnerClient.create_client(outgoing_queue)
+        refute_instance_of(NullClient, client)
+
+        first = pop_log_notification(outgoing_queue, Constant::MessageType::LOG)
+        assert_equal("Ruby LSP Rails booting server", first.params.message)
+
+        second = pop_log_notification(outgoing_queue, Constant::MessageType::LOG)
+        assert_match("Finished booting Ruby LSP Rails server", second.params.message)
+
+        client.shutdown
+        assert_predicate(client, :stopped?)
+        outgoing_queue.close
+      end
+    end
+  end
+end

test/test_helper.rb

@@ -48,5 +48,13 @@ def pop_result(server)
       )
       T.cast(result, RubyLsp::Result)
     end
+
+    def pop_log_notification(message_queue, type)
+      log = message_queue.pop
+      return log if log.params.type == type
+
+      log = message_queue.pop until log.params.type == type
+      log
+    end
   end
 end