@matheusbsbs / matheus-bagliano / commits / d88785e424

test-lib: set BASH_XTRACEFD automatically

Passing "-x" to a test script enables the shell's "set -x" tracing, which can help with tracking down the command that is causing a failure. Unfortunately, it can also _cause_ failures in some tests that redirect the stderr of a shell function. Inside the function the shell continues to respect "set -x", and the trace output is collected along with whatever stderr is generated normally by the function. You can see an example of this by running: ./t0040-parse-options.sh -x -i which will fail immediately in the first test, as it expects: test_must_fail some-cmd 2>output.err to leave output.err empty (but with "-x" it has our trace output). Unfortunately there isn't a portable or scalable solution to this. We could teach test_must_fail to disable "set -x", but that doesn't help any of the other functions or subshells. However, we can work around it by pointing the "set -x" output to our descriptor 4, which always points to the original stderr of the test script. Unfortunately this only works for bash, but it's better than nothing (and other shells will just ignore the BASH_XTRACEFD variable). The patch itself is a simple one-liner, but note the caveats in the accompanying comments. Automatic tests for our "-x" option may be a bit too meta (and a pain, because they are bash-specific), but I did confirm that it works correctly both with regular "-x" and with "--verbose-only=1". This works because the latter flips "set -x" off and on for particular tests (if it didn't, we would get tracing for all tests, as going to descriptor 4 effectively circumvents the verbose flag). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Jeff King committed May 11, 2016 at 09:44 UTC d88785e424aaf18aa3ca291c2299c599c000c6cb

2 files changed +16 -3

t/README

+3 -3

@@ -84,9 +84,9 @@ appropriately before running "make".

85 -x::

86 Turn on shell tracing (i.e., `set -x`) during the tests

87 - themselves. Implies `--verbose`. Note that this can cause

88 - failures in some tests which redirect and test the

89 - output of shell functions. Use with caution.

87 + themselves. Implies `--verbose`. Note that in non-bash shells,

88 + this can cause failures in some tests which redirect and test

89 + the output of shell functions. Use with caution.

91 -d::

92 --debug::

t/test-lib.sh

+13

@@ -322,6 +322,19 @@ else

322 exec 4>/dev/null 3>/dev/null

323 fi

324

325 +# Send any "-x" output directly to stderr to avoid polluting tests

326 +# which capture stderr. We can do this unconditionally since it

327 +# has no effect if tracing isn't turned on.

328 +#

329 +# Note that this sets up the trace fd as soon as we assign the variable, so it

330 +# must come after the creation of descriptor 4 above. Likewise, we must never

331 +# unset this, as it has the side effect of closing descriptor 4, which we

332 +# use to show verbose tests to the user.

333 +#

334 +# Note also that we don't need or want to export it. The tracing is local to

335 +# this shell, and we would not want to influence any shells we exec.

336 +BASH_XTRACEFD=4

337 +

338 test_failure=0

339 test_count=0

340 test_fixed=0