--- a/testing/runcppunittests.py
+++ b/testing/runcppunittests.py
@@ -15,17 +15,19 @@ log = mozlog.getLogger('cppunittests')
 @contextmanager
 def TemporaryDirectory():
     tempdir = tempfile.mkdtemp()
     yield tempdir
     shutil.rmtree(tempdir)
 
 class CPPUnitTests(object):
     # Time (seconds) to wait for test process to complete
-    TEST_PROC_TIMEOUT = 300
+    TEST_PROC_TIMEOUT = 1200
+    # Time (seconds) in which process will be killed if it produces no output.
+    TEST_PROC_NO_OUTPUT_TIMEOUT = 300
 
     def run_one_test(self, prog, env, symbols_path=None):
         """
         Run a single C++ unit test program.
 
         Arguments:
         * prog: The path to the test program to run.
         * env: The environment to use for running the program.
@@ -37,17 +39,18 @@ class CPPUnitTests(object):
         basename = os.path.basename(prog)
         log.info("Running test %s", basename)
         with TemporaryDirectory() as tempdir:
             proc = mozprocess.ProcessHandler([prog],
                                              cwd=tempdir,
                                              env=env)
             #TODO: After bug 811320 is fixed, don't let .run() kill the process,
             # instead use a timeout in .wait() and then kill to get a stack.
-            proc.run(timeout=CPPUnitTests.TEST_PROC_TIMEOUT)
+            proc.run(timeout=CPPUnitTests.TEST_PROC_TIMEOUT,
+                     outputTimeout=CPPUnitTests.TEST_PROC_NO_OUTPUT_TIMEOUT)
             proc.wait()
             if proc.timedOut:
                 log.testFail("%s | timed out after %d seconds",
                              basename, CPPUnitTests.TEST_PROC_TIMEOUT)
                 return False
             if mozcrash.check_for_crashes(tempdir, symbols_path,
                                           test_name=basename):
                 log.testFail("%s | test crashed", basename)