adb: add test for SIGHUP behavior.

This keeps regressing, so add a test to keep this from happening.

Bug: http://b/23603716
Bug: http://b/25965770
Bug: http://b/29565233
Test: Ran test with/without commit cd5d737, fails before, passes after
Change-Id: I8c431e10fc76da5a9fd404dd70f17bb8a8df24e6

adb/test_device.py

@@ -31,6 +31,7 @@ import string
 import subprocess
 import sys
 import tempfile
+import time
 import unittest
 
 import mock
@@ -495,6 +496,36 @@ class ShellTest(DeviceTest):
             self.assertEqual(input.splitlines(), stdout.splitlines())
             self.assertEqual('', stderr)
 
+    def test_sighup(self):
+        """Ensure that SIGHUP gets sent upon non-interactive ctrl-c"""
+        log_path = "/data/local/tmp/adb_signal_test.log"
+
+        # Clear the output file.
+        self.device.shell_nocheck(["echo", ">", log_path])
+
+        script = """
+            trap "echo SIGINT > {path}; exit 0" SIGINT
+            trap "echo SIGHUP > {path}; exit 0" SIGHUP
+            echo Waiting
+            while true; do sleep 100; done
+        """.format(path=log_path)
+
+        script = ";".join([x.strip() for x in script.strip().splitlines()])
+
+        process = self.device.shell_popen(
+            ["sh", "-c", "'{}'".format(script)], kill_atexit=False, stdout=subprocess.PIPE)
+
+        self.assertEqual("Waiting\n", process.stdout.readline())
+        process.send_signal(signal.SIGINT)
+        process.wait()
+
+        # Waiting for the local adb to finish is insufficient, since it hangs
+        # up immediately.
+        time.sleep(0.25)
+
+        stdout, _ = self.device.shell(["cat", log_path])
+        self.assertEqual(stdout.strip(), "SIGHUP")
+
 
 class ArgumentEscapingTest(DeviceTest):
     def test_shell_escaping(self):