Exercise pdeathsignal in tests

See: https://github.com/krallin/tini/pull/114#issuecomment-382756277

test/pdeathsignal/stage_1.py

@@ -0,0 +1,30 @@
+#!/usr/bin/env python
+from __future__ import print_function
+
+import os
+import sys
+import subprocess
+
+
+def main():
+    pid = os.getpid()
+
+    tini = sys.argv[1]
+    ret = sys.argv[2]
+    stage_2 = os.path.join(os.path.dirname(__file__), "stage_2.py")
+
+    cmd = [
+        tini,
+        "-vvv",
+        "-p",
+        "SIGUSR1",
+        "--",
+        stage_2,
+        str(pid),
+        ret
+    ]
+
+    subprocess.Popen(cmd).wait()
+
+if __name__ == "__main__":
+    main()

test/pdeathsignal/stage_2.py

@@ -0,0 +1,25 @@
+#!/usr/bin/env python
+from __future__ import print_function
+
+import os
+import sys
+import signal
+import time
+
+
+def main():
+    ret = sys.argv[2]
+
+    def handler(*args):
+        with open(ret, "w") as f:
+            f.write("ok")
+        sys.exit(0)
+
+    signal.signal(signal.SIGUSR1, handler)
+    pid = int(sys.argv[1])
+
+    os.kill(pid, signal.SIGKILL)
+    time.sleep(5)
+
+if __name__ == "__main__":
+    main()

test/run_inner_tests.py

@@ -9,6 +9,7 @@ import psutil
 import bitmap
 import re
 import itertools
+import tempfile
 
 DEVNULL = open(os.devnull, 'wb')
 
@@ -133,7 +134,7 @@ def main():
     assert ret == 1, "Reaping test succeeded (it should have failed)!"
 
     # Test that the signals are properly in place here.
-    print "running signal configuration test"
+    print "Running signal configuration test"
 
     p = subprocess.Popen([os.path.join(build, "sigconf-test"), tini, "cat", "/proc/self/status"], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
     out, err = p.communicate()
@@ -156,6 +157,21 @@ def main():
             # Use signum - 1 because the bitmap is 0-indexed but represents signals strting at 1
             assert (signum - 1) in props[signal_set_name].nonzero(), "{0} ({1}) is missing in {2}!".format(SIGNUM_TO_SIGNAME[signum], signum, signal_set_name)
 
+    # Test parent death signal handling.
+    if not args_disabled:
+        print "Running parent death signal test"
+        f = tempfile.NamedTemporaryFile()
+        try:
+            p = subprocess.Popen(
+                [os.path.join(src, "test", "pdeathsignal", "stage_1.py"), tini, f.name],
+                stdout=DEVNULL, stderr=DEVNULL
+            )
+            p.wait()
+
+            busy_wait(lambda: open(f.name).read() == "ok", 10)
+        finally:
+            f.close()
+
     print "---------------------------"
     print "All done, tests as expected"
     print "---------------------------"