Adds test_kill to buildslave tests

Adds a unit test which ensures the process will receive SIGKILL if
SIGTERM fails to end the process.

slave/buildslave/test/unit/test_runprocess.py

@@ -18,6 +18,7 @@
 import os
 import time
 import signal
+from mock import Mock
 
 from twisted.trial import unittest
 from twisted.internet import task, defer, reactor
@@ -553,6 +554,46 @@ def check_dead(_):
         runproc_d.addCallback(check_dead)
         return defer.gatherResults([pidfile_d, runproc_d])
 
+    def test_kill(self, interruptSignal=None):
+
+        # Tests that the process will receive SIGKILL if SIGTERM
+        # is ignored.
+        pidfile = self.newPidfile()
+        self.pid = None
+        b = FakeSlaveBuilder(False, self.basedir)
+        s = runprocess.RunProcess(b,
+                scriptCommand('write_pidfile_and_sleep', pidfile),
+                self.basedir)
+        runproc_d = s.start()
+        pidfile_d = self.waitForPidfile(pidfile)
+
+        def check_alive(pid):
+            # Create a mock process that will ignore SIGTERM and only
+            # forward on the signal when we recieve SIGKILL
+            mock_process = Mock(wraps=s.process)
+            mock_process.pgid = None # Skips over group SIGTERM
+            process = s.process
+            def _mock_signalProcess(sig):
+                if sig == "TERM":
+                    raise OSError
+                else:
+                    process.signalProcess(sig)
+            mock_process.signalProcess = _mock_signalProcess
+            s.process = mock_process
+
+            self.pid = pid # for use in check_dead
+            # test that the process is still alive
+            self.assertAlive(pid)
+            # and tell the RunProcess object to kill it
+            s.kill("diaf")
+        pidfile_d.addCallback(check_alive)
+
+        def check_dead(_):
+            self.failUnlessEqual(s.killedBy, "KILL")
+            self.assertDead(self.pid)
+        runproc_d.addCallback(check_dead)
+        return defer.gatherResults([pidfile_d, runproc_d])
+
     def test_pgroup_usePTY(self):
         return self.do_test_pgroup(usePTY=True)