From 8c7fd53e655b4d8c50ab65b853c049e61eb6f3c0 Mon Sep 17 00:00:00 2001
From: Yordis Prieto <yordis.prieto@gmail.com>
Date: Tue, 14 Apr 2026 23:45:05 -0400
Subject: [PATCH 1/2] fix(telemetry): isolate test OpenTelemetry configuration

Signed-off-by: Yordis Prieto <yordis.prieto@gmail.com>
---
 config/test.exs                    |  2 +
 test/support/opentelemetry_case.ex | 61 ++++++++++++++++++++++++++----
 2 files changed, 56 insertions(+), 7 deletions(-)

diff --git a/config/test.exs b/config/test.exs
index ec55c6ca..004b4f63 100644
--- a/config/test.exs
+++ b/config/test.exs
@@ -14,6 +14,8 @@ config :ex_unit,
   capture_log: [level: :debug],
   exclude: [:distributed, :eventstore_adapter]
 
+config :opentelemetry, processors: []
+
 config :commanded,
   assert_receive_event_timeout: 100,
   refute_receive_event_timeout: 100,
diff --git a/test/support/opentelemetry_case.ex b/test/support/opentelemetry_case.ex
index a8d59d5e..bf81060a 100644
--- a/test/support/opentelemetry_case.ex
+++ b/test/support/opentelemetry_case.ex
@@ -25,14 +25,15 @@ defmodule Commanded.OpenTelemetryCase do
   end
 
   setup do
-    :application.stop(:opentelemetry)
-    :application.set_env(:opentelemetry, :tracer, :otel_tracer_default)
+    previous_env = Application.get_all_env(:opentelemetry)
+    previously_started? = started?(:opentelemetry)
 
-    :application.set_env(:opentelemetry, :processors, [
-      {:otel_batch_processor, %{scheduled_delay_ms: 1, exporter: {:otel_exporter_pid, self()}}}
-    ])
-
-    :application.start(:opentelemetry)
+    restart_opentelemetry(
+      tracer: :otel_tracer_default,
+      processors: [
+        {:otel_batch_processor, %{scheduled_delay_ms: 1, exporter: {:otel_exporter_pid, self()}}}
+      ]
+    )
 
     on_exit(fn ->
       commanded_events = [
@@ -61,8 +62,54 @@ defmodule Commanded.OpenTelemetryCase do
           handler <- :telemetry.list_handlers(event) do
         :telemetry.detach(handler.id)
       end
+
+      restore_opentelemetry(previous_env, previously_started?)
     end)
 
     :ok
   end
+
+  defp started?(application) do
+    Enum.any?(Application.started_applications(), fn {started_application, _description, _version} ->
+      started_application == application
+    end)
+  end
+
+  defp restart_opentelemetry(env) do
+    stop_opentelemetry()
+
+    Enum.each(env, fn {key, value} ->
+      Application.put_env(:opentelemetry, key, value)
+    end)
+
+    Application.start(:opentelemetry)
+  end
+
+  defp restore_opentelemetry(previous_env, previously_started?) do
+    stop_opentelemetry()
+
+    current_keys =
+      :opentelemetry
+      |> Application.get_all_env()
+      |> Keyword.keys()
+
+    Enum.each(current_keys -- Keyword.keys(previous_env), fn key ->
+      Application.delete_env(:opentelemetry, key)
+    end)
+
+    Enum.each(previous_env, fn {key, value} ->
+      Application.put_env(:opentelemetry, key, value)
+    end)
+
+    if previously_started? do
+      Application.start(:opentelemetry)
+    end
+  end
+
+  defp stop_opentelemetry do
+    case Application.stop(:opentelemetry) do
+      :ok -> :ok
+      {:error, {:not_started, :opentelemetry}} -> :ok
+    end
+  end
 end

From 691dda5beed8bfa8b43efa7d0c55233b84fb82e8 Mon Sep 17 00:00:00 2001
From: Yordis Prieto <yordis.prieto@gmail.com>
Date: Tue, 14 Apr 2026 23:57:17 -0400
Subject: [PATCH 2/2] fix(telemetry): rely on test defaults for trace isolation

Signed-off-by: Yordis Prieto <yordis.prieto@gmail.com>
---
 test/support/opentelemetry_case.ex | 61 ++++--------------------------
 1 file changed, 7 insertions(+), 54 deletions(-)

diff --git a/test/support/opentelemetry_case.ex b/test/support/opentelemetry_case.ex
index bf81060a..a8d59d5e 100644
--- a/test/support/opentelemetry_case.ex
+++ b/test/support/opentelemetry_case.ex
@@ -25,15 +25,14 @@ defmodule Commanded.OpenTelemetryCase do
   end
 
   setup do
-    previous_env = Application.get_all_env(:opentelemetry)
-    previously_started? = started?(:opentelemetry)
+    :application.stop(:opentelemetry)
+    :application.set_env(:opentelemetry, :tracer, :otel_tracer_default)
 
-    restart_opentelemetry(
-      tracer: :otel_tracer_default,
-      processors: [
-        {:otel_batch_processor, %{scheduled_delay_ms: 1, exporter: {:otel_exporter_pid, self()}}}
-      ]
-    )
+    :application.set_env(:opentelemetry, :processors, [
+      {:otel_batch_processor, %{scheduled_delay_ms: 1, exporter: {:otel_exporter_pid, self()}}}
+    ])
+
+    :application.start(:opentelemetry)
 
     on_exit(fn ->
       commanded_events = [
@@ -62,54 +61,8 @@ defmodule Commanded.OpenTelemetryCase do
           handler <- :telemetry.list_handlers(event) do
         :telemetry.detach(handler.id)
       end
-
-      restore_opentelemetry(previous_env, previously_started?)
     end)
 
     :ok
   end
-
-  defp started?(application) do
-    Enum.any?(Application.started_applications(), fn {started_application, _description, _version} ->
-      started_application == application
-    end)
-  end
-
-  defp restart_opentelemetry(env) do
-    stop_opentelemetry()
-
-    Enum.each(env, fn {key, value} ->
-      Application.put_env(:opentelemetry, key, value)
-    end)
-
-    Application.start(:opentelemetry)
-  end
-
-  defp restore_opentelemetry(previous_env, previously_started?) do
-    stop_opentelemetry()
-
-    current_keys =
-      :opentelemetry
-      |> Application.get_all_env()
-      |> Keyword.keys()
-
-    Enum.each(current_keys -- Keyword.keys(previous_env), fn key ->
-      Application.delete_env(:opentelemetry, key)
-    end)
-
-    Enum.each(previous_env, fn {key, value} ->
-      Application.put_env(:opentelemetry, key, value)
-    end)
-
-    if previously_started? do
-      Application.start(:opentelemetry)
-    end
-  end
-
-  defp stop_opentelemetry do
-    case Application.stop(:opentelemetry) do
-      :ok -> :ok
-      {:error, {:not_started, :opentelemetry}} -> :ok
-    end
-  end
 end