[PATCH v2] 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. It invokes "$SHELL_PATH" to provide a sane shell
for the user.

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 17.01.2012 20:15, schrieb Junio C Hamano:
> Jens Lehmann <Jens.Lehmann@web.de> writes:
> What I cared was more about the hardcoded "bash". Believe it or not, there
> are boxes that lack it, and there are people who prefer other shells for
> their interactive work. At the very least, invoke "$SHELL_PATH" instead of
> bash there, perhaps?

Sure, I changed that in this version and explained it in the commit
message.

> If we wanted to allow an ad-hoc debugging of test scripts to sprinkle
> "test_pause $cmd", we might need to do something like:
> 
>> +test_pause () {
>> +	if test "$verbose" = t; then
>> +		bash <&6 >&3 2>&4
> 		${1-"$SHELL_PATH"} <&6 >&3 2>&4
>> +	else
>> +		error >&5 "test_pause requires --verbose"
>> +	fi
>> +}
> 
> but I do not think that is worth it. The debugging developer should easily
> be able to run gdb or whatever from the interactive shell you are giving
> here.

That's what I always do, so I'm fine with what this patch provides. And
now the fact that you can temporarily pause a test and explore the trash
directory is documented too ;-)


 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..709a300 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 "$verbose" = t; then
+		"$SHELL_PATH" <&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.rc1.1.g8dae2