Re: [PATCH] test-lib: add the test_bash convenience function

[Jeff King <peff@peff.net>]

On Sun, Jan 15, 2012 at 09:00:41PM +0100, Jens Lehmann wrote:

> Since 781f76b15 (test-lib: redirect stdin of tests) you can't simply put a
> "bash &&" into a test for debugging purposes anymore. Instead you'll have
> to use "bash <&6 >&3 2>&4".

Yeah, an unfortunate side effect.

If you're not relying on particular state in the middle of a chain of
commands, you can just put the "bash" outside of the test_expect_*. But
sometimes you do care about having it in the middle.

> As that invocation is not that easy to remember add the test_bash
> convenience function. This function also checks if the -v flag is given
> and will complain if that is not the case instead of letting the test
> hang until ^D is pressed.

Nice. Many times I have added such a "bash" or "gdb" invocation then
forgotten "-v", only to scratch my head at why the test seemed to be
hanging.

Two minor nits on the patch itself:

> +# Stop execution and start a bash shell. This is useful for debugging tests
> +# and only makes sense together with "-v".
> +
> +test_bash () {
> +	if test "$verbose" = t; then
> +		bash <&6 >&3 2>&4
> +	else
> +		say >&5 "skipping test_bash as it makes no sense without -v"
> +	fi
> +}

1. It may be worth putting a warning in the comment that this is never
   to be used in a real test, but only temporarily inserted.

2. I do this not just with bash, but with "gdb". I wonder if it is worth
   making this "test_foo bash", for some value of "foo" (the ones that
   occur to me are "debug" and "run", but of course they are taken).

   Actually, I wonder if the existing test_debug could handle this
   already (though you do have to remember to add "--debug" to your
   command line, then).

-Peff