[PATCH] test-lib: add the test_pause convenience function

[Jens Lehmann <Jens.Lehmann@web.de>]

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".

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

Signed-off-by: Jens Lehmann <Jens.Lehmann@web.de>
---

Am 16.01.2012 23:51, schrieb Junio C Hamano:
> Jeff King <peff@peff.net> writes:
> 
>> 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:
>> ...
>> 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).
> 
> I wondered the same thing from a different angle. My first reaction was
> "Why is this called 'bash' not 'sh'?" which naturally led to the same
> direction as yours "why not an arbitrary command 'test_debug xxx'?"
> 
> test_pause perhaps?

I really don't care deeply about the name, so test_pause is absolutely
ok for me. I added some documentation in t/README too and made it an
error when --verbose is not used.

Is it ok to invoke bash here or should sh be used?


 t/README      |   13 +++++++++++++
 t/test-lib.sh |   13 +++++++++++++
 2 files changed, 26 insertions(+), 0 deletions(-)

diff --git a/t/README b/t/README
index c85abaf..c09c582 100644
--- a/t/README
+++ b/t/README
@@ -548,6 +548,19 @@ library for your script to use.
 		...
 	'

+ - test_pause
+
+	This command is useful for writing and debugging tests and must be
+	removed before submitting. It halts the execution of the test and
+	spawns a shell in the trash directory. Exit the shell to continue
+	the test. Example:
+
+	test_expect_success 'test' '
+		git do-something >actual &&
+		test_pause &&
+		test_cmp expected actual
+	'
+
 Prerequisites
 -------------

diff --git a/t/test-lib.sh b/t/test-lib.sh
index a65dfc7..85084c4 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -329,6 +329,19 @@ test_tick () {
 	export GIT_COMMITTER_DATE GIT_AUTHOR_DATE
 }

+# Stop execution and start a shell. This is useful for debugging tests and
+# only makes sense together with "-v".
+#
+# Be sure to remove all invocations of this command before submitting.
+
+test_pause () {
+	if test "$verbose" = t; then
+		bash <&6 >&3 2>&4
+	else
+		error >&5 "test_pause requires --verbose"
+	fi
+}
+
 # Call test_commit with the arguments "<message> [<file> [<contents>]]"
 #
 # This will commit a file with the given contents and the given commit
-- 
1.7.9.rc1.2.g0b847.dirty