test: verify finit restarts crashing services & registers new PID

We extend the service.sh to emulate a well behaving service that creates
and removes its own PID file.

The new test emulates a crash by sending SIGKILL to service.sh.  We then
verify that Finit restarts it, and eventually registers the new PID when
the services recreates the PID file.

Issue #226

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

test/start-kill-service.sh

@@ -0,0 +1,35 @@
+#!/bin/sh
+
+set -eu
+
+TEST_DIR=$(dirname "$0")
+
+# shellcheck source=/dev/null
+. "$TEST_DIR/tenv/lib.sh"
+
+test_teardown() {
+    say "Test done $(date)"
+    say "Running test teardown."
+
+    texec rm -f "$FINIT_CONF"
+    texec rm -f /test_assets/service.sh
+}
+
+say "Test start $(date)"
+
+cp "$TEST_DIR"/common/service.sh "$TENV_ROOT"/test_assets/
+
+say "Add service stanza in $FINIT_CONF"
+texec sh -c "echo 'service [2345] kill:20 log /test_assets/service.sh -- Test service' > $FINIT_CONF"
+
+say 'Reload Finit'
+texec sh -c "initctl reload"
+#texec sh -c "initctl status"
+
+retry 'assert_num_children 1 service.sh'
+
+say 'Simulate service crash (kill -9 ..)'
+texec sh -c "kill -9 \$(cat /run/service.pid)"
+
+retry 'assert_new_pid service.sh /run/service.pid'
+retry 'assert_num_children 1 service.sh'