[Zope-Coders] Re: Zope tests: 4 OK, 2 Failed

[Tim Peters]

[Stefan H. Holek, on testRunIgnoresParentSignals]
> Right. The test only fails in the nightly runs. It passes fine when I
> run the tests from the command line. Let's see what I can do
> about that...

A good start would be to rewrite the test, so that it becomes possible
to guess something about the cause of failure when it does fail.  For
example, the test's

        try:
            response = send_action('status\n', zdrun_socket) or ''
        except socket.error, msg:
            response = ''

is silly, because send_action() suppresses socket.error.  IOW, the
try/except block here is useless.  Better would be, e.g.,

        response = (send_action('status\n', zdrun_socket) or
                          "send_action failed")

Better still may be to change send_action() to record why it fails
when it fails.

Then the actual raising of a failure loses all useful information:

        self.assert_(len(params) > 1)

That doesn't tell you whether the response was empty, or not empty but
not of the expected form, or what.  Better here would be, e.g.,

    if '\n' not in response:
        self.fail("expected at least one newline in response %r" %
                   response)

*If* it's failing because spawnvp doesn't have time to get the new
processes running, what actually happens in this test is that its
first send_action() call suppresses a socket.error with a detail of
the form

    (2, 'No such file or directory')

The test turns send_action's None return in that case into an empty
string, and then splitting an empty string by '\n' yields the list

    ['']

and so

        self.assert_(len(params) > 1)

triggers.  I'm guessing that is what's happening, too, but it's
impossible to be sure of that now from the test's useless failure
output.