diff --git a/config/runtime.exs b/config/runtime.exs
index 7b7bf1a5..d7c5492c 100644
--- a/config/runtime.exs
+++ b/config/runtime.exs
@@ -13,7 +13,7 @@ require Logger
 if config_env() == :test do
   for repo <- [Microwaveprop.Repo] do
     existing = Application.get_env(:microwaveprop, repo, [])
-    Application.put_env(:microwaveprop, repo, Keyword.put(existing, :pool, DBConnection.Ownership))
+    Application.put_env(:microwaveprop, repo, Keyword.put(existing, :pool, Ecto.Adapters.SQL.Sandbox))
   end
 end
 
diff --git a/nix/shell.nix b/nix/shell.nix
index 3aaae63c..9bae14d3 100644
--- a/nix/shell.nix
+++ b/nix/shell.nix
@@ -229,8 +229,8 @@ mkShell {
     export SECRET_KEY_BASE="dev_secret_key_base_at_least_64_bytes_long_for_phoenix_to_accept_it_safely"
     export RELEASE_COOKIE="dev_release_cookie_for_distributed_erlang"
 
-    # Development environment
-    export MIX_ENV=dev
+    # Mix defaults to :dev for most tasks and :test for mix test;
+    # don't force MIX_ENV — let Mix select automatically.
     export PHX_HOST=localhost
     export PORT=4000
 
diff --git a/test/test_helper.exs b/test/test_helper.exs
index f3f0d2c2..06eaa676 100644
--- a/test/test_helper.exs
+++ b/test/test_helper.exs
@@ -67,6 +67,15 @@ Logger.put_module_level(
   :critical
 )
 
+# Silence expected error-path noise during tests. Background workers
+# (NarrFetch, etc.) run inline under `testing: :inline` and hit stubbed
+# HTTP 500 responses — the warnings and Oban job-exception logs are
+# deliberate test behaviour, not bugs.
+Logger.put_module_level(
+  [Microwaveprop.Workers.NarrFetchWorker, Microwaveprop.ObanErrorReporter],
+  :critical
+)
+
 if Code.ensure_loaded?(Mox) do
   Mox.defmock(Microwaveprop.Valkey.MockAdapter, for: Microwaveprop.Valkey.Adapter)
 end