Fix tests failing due to epmdless

apps/expert/lib/expert/engine_node.ex

@@ -31,10 +31,25 @@ defmodule Expert.EngineNode do
       this_node = inspect(Node.self())
       dist_port = Expert.EPMD.dist_port()
 
+      # Detect test env by checking if manager node name (see test_helper.exs)
+      is_test? = Node.self() |> to_string() |> String.starts_with?("expert-testing-")
+
+      # In release, use full epmdless config.
+      # In test, skip -erl_epmd_port and -dist_listen false b/c:
+      #   - Manager uses EPMD (can't load Expert.EPMD before Elixir runtime)
+      #   - Project needs to query EPMD on default port (4369) to find manager
+      #   - :global registry needs bidirectional communication
+      erl_flags =
+        if is_test? do
+          "-start_epmd false"
+        else
+          "-start_epmd false -erl_epmd_port #{dist_port} -dist_listen false"
+        end
+
       args =
         [
           "--erl",
-          "-start_epmd false -erl_epmd_port #{dist_port} -dist_listen false",
+          erl_flags,
           "--name",
           Project.node_name(state.project),
           "--cookie",

apps/expert/test/test_helper.exs

@@ -1,11 +1,31 @@
 Application.ensure_all_started(:snowflake)
 Application.ensure_all_started(:refactorex)
+
+# Start EPMD for the test manager node.
+# We can't use Expert.EPMD here because the kernel needs epmd_module before
+# Elixir loads. In releases, Elixir is in the boot sequence. In mix test, it's not.
+# Compromise: manager uses EPMD, project nodes are epmdless (see engine_node.ex).
 {"", 0} = System.cmd("epmd", ~w(-daemon))
-random_number = :rand.uniform(500)
 
 with :nonode@nohost <- Node.self() do
+  random_number = :rand.uniform(500)
+
   {:ok, _pid} =
-    :net_kernel.start(:"testing-#{random_number}@127.0.0.1", %{name_domain: :longnames})
+    :net_kernel.start(:"expert-testing-#{random_number}@127.0.0.1", %{name_domain: :longnames})
+end
+
+# Query our distribution port and store it in persistent_term
+# This enables epmdless configuration for project nodes spawned during tests
+node_name =
+  Node.self()
+  |> to_string()
+  |> String.split("@")
+  |> hd()
+  |> String.to_charlist()
+
+case :erl_epmd.port_please(node_name, ~c"127.0.0.1") do
+  {:port, port, _version} -> :persistent_term.put(:expert_dist_port, port)
+  _error -> :ok
 end
 
 Engine.Module.Loader.start_link(nil)