From cd4f35abdfe30ac5f8b78696d443400e73f77e1e Mon Sep 17 00:00:00 2001
From: Tim Abbott <tabbott@zulipchat.com>
Date: Fri, 7 Jul 2017 13:36:03 -0700
Subject: [PATCH] test-backend: Don't run tests in parallel with given test
 files.

It's usually slower to run in parallel with a single file.
---
 tools/test-backend | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/test-backend b/tools/test-backend
index 43a8308c4a..f30b4d761f 100755
--- a/tools/test-backend
+++ b/tools/test-backend
@@ -226,6 +226,9 @@ if __name__ == "__main__":
         failed_tests = get_failed_tests()
         if failed_tests:
             args = failed_tests
+    if len(args) > 0:
+        # If we passed a specific set of tests, run in serial mode.
+        options.processes = 1
 
     # to transform forward slashes '/' present in the argument into dots '.'
     for suite in args: