Subject: Re: [PATCH 3/3] t/README: document how to loop around test cases

From: Junio C Hamano <[email-masked]>
Date: Thu, 21 Mar 2024 10:12:40 -0700

Patrick Steinhardt <[email-masked]> writes:

> In some cases it makes sense to loop around test cases so that we can
> execute the same test with slightly different arguments. There are some
> gotchas around quoting here though that are easy to miss and that may
> lead to easy-to-miss errors and portability issues.
>
> Document the proper way to do this in "t/README".
>
> Signed-off-by: Patrick Steinhardt <[email-masked]>
> ---
>  t/README | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
>
> diff --git a/t/README b/t/README
> index 36463d0742..d56401a254 100644
> --- a/t/README
> +++ b/t/README
> @@ -721,6 +721,25 @@ The "do's:"
>     Note that we still &&-chain the loop to propagate failures from
>     earlier commands.
>  
> + - Repeat tests with slightly different arguments in a loop.
> +
> +   In some cases it may make sense to re-run the same set of tests with
> +   different options or commands to ensure that the command behaves
> +   despite the different parameters. This can be achieved by looping
> +   around a specific parameter:
> +
> +	for arg in '' "--foo"
> +	do
> +		test_expect_success "test command ${arg:-without arguments}" '
> +			command $arg
> +		'
> +	done
> +
> +  Note that while the test title uses double quotes ("), the test body
> +  should continue to use single quotes ('). The loop variable will be
> +  accessible regardless of the single quotes as the test body is passed
> +  to `eval`.

We also want to say that they are not equivalent, don't we?

        for var in '' a 'b"c'
        do
                test_expect_success "with dq <$var>" "
                        echo \"$var\"
                "
        done

breaks, but if we use

                test_expect_success "with sq <$var>" '
                        echo "$var"
                '

in the loop, it works as expected.

Other than that, all three patches do make sense.

Thanks.