diff --git a/test/configuration/traefik/static_test.rb b/test/configuration/traefik/static_test.rb
new file mode 100644
index 00000000..123708cc
--- /dev/null
+++ b/test/configuration/traefik/static_test.rb
@@ -0,0 +1,26 @@
+require "test_helper"
+
+class ConfigurationTraefikStaticTest < ActiveSupport::TestCase
+  setup do
+    @deploy = {
+      service: "app", image: "dhh/app",
+      registry: { "username" => "dhh", "password" => "secret" },
+      env: { "REDIS_URL" => "redis://x/y" },
+      servers: [ "1.1.1.1", "1.1.1.2" ],
+      volumes: ["/local/path:/container/path"],
+      traefik: {}
+    }
+
+    @config = Kamal::Configuration.new(@deploy)
+  end
+
+  test "env_file" do
+    ENV["EXAMPLE_API_KEY"] = "456"
+    @config.traefik["env"] = { "secret" => %w[EXAMPLE_API_KEY] }
+    traefik_static = Kamal::Configuration::Traefik::Static.new(config: @config)
+
+    assert_equal "EXAMPLE_API_KEY=456\n", traefik_static.env_file
+  ensure
+    ENV.delete "EXAMPLE_API_KEY"
+  end
+end