How to assert "throw" by ERT?

[Oleksandr Gavenko]

ERT is Emacs Lisp Regression Testing and ERT packed in GNU Emacs.

I want to check that my function throw on some input data:

  (defun foo (arg) (unless arg (throw :invalid-arg nil)))

I write:

  (ert-deftest foo-fail-test ()
    (should-error (foo nil) :type :invalid-arg)
    )

but seems this is wrong usege or 'should-error'.

Please help me with example...

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Best regards!