[PATCH 4/5] test-run-command: test for gracefully aborting

[Stefan Beller <sbeller@google.com>]

We reuse the get_next_task callback which would stop after invoking the
test program 4 times. However as we have only 3 parallel processes started
(We pass in 3 as max parallel processes and 3 is smaller than the spawn
cap in run-command, so we will start the 3 processes in the first run
deterministically), then the abort logic from the new task_finished
callback kicks in and prevents the parallel processing engine to start
any more processes.

As the task_finished is unconditional, we will see its output 3 times, too.

Signed-off-by: Stefan Beller <sbeller@google.com>
---
 t/t0061-run-command.sh | 14 ++++++++++++++
 test-run-command.c     | 14 ++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/t/t0061-run-command.sh b/t/t0061-run-command.sh
index 49aa3db..0af77cd 100755
--- a/t/t0061-run-command.sh
+++ b/t/t0061-run-command.sh
@@ -67,4 +67,18 @@ test_expect_success 'run_command runs in parallel' '
 	test_cmp expect actual
 '
 
+cat >expect <<-EOF
+preloaded output of a child
+asking for a quick stop
+preloaded output of a child
+asking for a quick stop
+preloaded output of a child
+asking for a quick stop
+EOF
+
+test_expect_success 'run_command is asked to abort gracefully' '
+	test-run-command run-command-abort-3 false 2>actual &&
+	test_cmp expect actual
+'
+
 test_done
diff --git a/test-run-command.c b/test-run-command.c
index 699d9e9..4b59482 100644
--- a/test-run-command.c
+++ b/test-run-command.c
@@ -34,6 +34,16 @@ static int parallel_next(void** task_cb,
 	return 1;
 }
 
+static int task_finished(int result,
+			 struct child_process *cp,
+			 struct strbuf *err,
+			 void *pp_cb,
+			 void *pp_task_cb)
+{
+	strbuf_addf(err, "asking for a quick stop\n");
+	return 1;
+}
+
 int main(int argc, char **argv)
 {
 	struct child_process proc = CHILD_PROCESS_INIT;
@@ -55,6 +65,10 @@ int main(int argc, char **argv)
 		exit(run_processes_parallel(4, parallel_next,
 					    NULL, NULL, &proc));
 
+	if (!strcmp(argv[1], "run-command-abort-3"))
+		exit(run_processes_parallel(3, parallel_next,
+					    NULL, task_finished, &proc));
+
 	fprintf(stderr, "check usage\n");
 	return 1;
 }
-- 
2.5.0.285.g8fe9b61.dirty