diff --git a/test/test_helper.exs b/test/test_helper.exs
index 3a05c78..4b8abf0 100644
--- a/test/test_helper.exs
+++ b/test/test_helper.exs
@@ -10,6 +10,8 @@ Application.put_env(:pinchflat, :http_client, HTTPClientMock)
 Mox.defmock(UserScriptRunnerMock, for: Pinchflat.Lifecycle.UserScripts.UserScriptCommandRunner)
 Application.put_env(:pinchflat, :user_script_runner, UserScriptRunnerMock)
 
+if System.get_env("EX_CHECK"), do: Code.put_compiler_option(:warnings_as_errors, true)
+
 ExUnit.start()
 Ecto.Adapters.SQL.Sandbox.mode(Pinchflat.Repo, :manual)
 Faker.start()
diff --git a/tooling/.check.exs b/tooling/.check.exs
index 98ca0e2..87b90ff 100644
--- a/tooling/.check.exs
+++ b/tooling/.check.exs
@@ -17,7 +17,8 @@
     {:formatter, env: %{"MIX_ENV" => "test"}},
     {:sobelow, "mix sobelow --config"},
     {:prettier_formatting, "yarn run lint:check", fix: "yarn run lint:fix"},
-    {:npm_test, false}
+    {:npm_test, false},
+    {:ex_unit, env: %{"MIX_ENV" => "test", "EX_CHECK" => "1"}}
 
     ## curated tools may be disabled (e.g. the check for compilation warnings)
     # {:compiler, false},