   end
 
   test "c helper list" do
+    assert_raise UndefinedFunctionError, "undefined function: Helpers_test_module.run/0", fn ->
+      Helpers_test_module.run
+    end
+
     File.write! "test-module-code-1.ex", test_module_code
     File.write! "test-module-code-2.ex", another_test_module
     assert c(["test-module-code-1.ex", "test-module-code-2.ex"]) |> Enum.sort

    end

    File.write! "test-module-code.ex", test_module_code
    # FIXME: `r Helpers_test_module` returns :nosource
    assert c("test-module-code.ex") == [Helpers_test_module]
    assert r(Helpers_test_module) == [Helpers_test_module]

    assert r == [Helpers_test_module]

  end

  test "c helper multiple modules" do
    assert_raise UndefinedFunctionError, "undefined function: Helpers_test_module.run/0", fn ->
      Helpers_test_module.run
    end

    File.write! "test-module-code.ex", test_module_code <> "\n" <> another_test_module
    assert c("test-module-code.ex") |> Enum.sort == [Another_test_module,Helpers_test_module]
    assert Helpers_test_module.run == :run
