don't read any output in check_async_cmd if output_read_size is set to 0

Author: boegel

easybuild/tools/run.py

@@ -263,9 +263,10 @@ def check_async_cmd(proc, cmd, owd, start_time, cmd_log, output_read_size=1024,
     :result: dict value with result of the check (boolean 'done', 'exit_code', 'output')
     """
     # use small read size, to avoid waiting for a long time until sufficient output is produced
-    add_out = get_output_from_process(proc, read_size=output_read_size)
-    _log.debug("Additional output from asynchronous command '%s': %s" % (cmd, add_out))
-    output += add_out
+    if output_read_size:
+        add_out = get_output_from_process(proc, read_size=output_read_size)
+        _log.debug("Additional output from asynchronous command '%s': %s" % (cmd, add_out))
+        output += add_out
 
     exit_code = proc.poll()
     if exit_code is None:

test/framework/run.py

@@ -639,6 +639,13 @@ def test_run_cmd_async(self):
 
         # also test use of check_async_cmd on verbose test command
         cmd_info = run_cmd(verbose_test_cmd, asynchronous=True)
+
+        # with output_read_size set to 0, no output is read yet, only status of command is checked
+        res = check_async_cmd(*cmd_info, output_read_size=0)
+        self.assertEqual(res['done'], False)
+        self.assertEqual(res['exit_code'], None)
+        self.assertEqual(res['output'], '')
+
         res = check_async_cmd(*cmd_info)
         self.assertEqual(res['done'], False)
         self.assertEqual(res['exit_code'], None)