adding tests and CLI check for 0 or less input for duration

rq/cli/cli.py

@@ -196,8 +196,13 @@ def worker(url, config, burst, name, worker_class, job_class, queue_class, path,
 @click.option('--duration', help='Seconds you want the workers to be suspended.  Default is forever.', type=int)
 def suspend(url, config, duration):
     """Suspends all workers, to resume run `rq resume`"""
+    if duration is not None and duration < 1:
+        click.echo("Duration must be an integer greater than 1")
+        sys.exit(1)
+
     connection = connect(url, config)
     connection_suspend(connection, duration)
+
     if duration:
         msg = """Suspending workers for {} seconds.  No new jobs will be started during that time, but then will
         automatically resume""".format(duration)

tests/test_cli.py

@@ -90,9 +90,20 @@ def test_suspend_with_ttl(self):
         """rq suspend -u <url> --duration=2
         """
         runner = CliRunner()
-        result = runner.invoke(main, ['suspend', '-u', self.redis_url, '--duration', 2])
+        result = runner.invoke(main, ['suspend', '-u', self.redis_url, '--duration', 1])
         self.assert_normal_execution(result)
 
+    def test_suspend_with_invalid_ttl(self):
+        """rq suspend -u <url> --duration=0
+        """
+        runner = CliRunner()
+        result = runner.invoke(main, ['suspend', '-u', self.redis_url, '--duration', 0])
+
+        self.assertEqual(result.exit_code, 1)
+        self.assertIn("Duration must be an integer greater than 1", result.output)
+
+
+