Feature/fix spurious stats test

.github/workflows/elixir.yml

@@ -49,7 +49,7 @@ jobs:
         run: mix compile --warnings-as-errors
 
       - name: Run Tests
-        run: mix test
+        run: ./test.sh
 
       - name: Run dialyzer static code analysis
         run: mix dialyzer

test.sh

@@ -1,2 +1,10 @@
 #!/bin/sh
-SIGNALTOWER_PORT="4235" mix test
+SIGNALTOWER_PORT="4235" mix test test/room_test.exs test/session_test.exs test/test_helper.exs
+ok=$?
+
+# prometheus_stats_test test counters incrementing, but I assume this conflicts with
+# room_test and session_test as these also call stats functions in parallel.
+# I think those test file runs share the module state which own the prometheus counters.
+#
+# To workaround this issue, we run conflicting test files not together.
+mix test test/prometheus_stats_test.exs && $ok

test/session_test.exs

@@ -226,7 +226,7 @@ defmodule SessionTest do
       %{
         "event" => "ping"
       },
-      @initial_state()
+      @initial_state
     )
 
     assert_receive {:to_user, %{event: "pong"}}