test infra: force rerun to use parallel runner

We've now seen the rerun test phase hang in a few
scenarios.  Eliminate the serial test runner (which
is not exercised nearly as much as the others), by
using a multi-worker test runner strategy with a single
worker.  This should rule out whether this is related
to the serial test runner strategy.

llvm-svn: 255880

1 files changed, 5 insertions, 1 deletions

diff --git a/lldb/packages/Python/lldbsuite/test/dosep.py b/lldb/packages/Python/lldbsuite/test/dosep.py
index 792d3679670..3443c6b3a77 100644
--- a/lldb/packages/Python/lldbsuite/test/dosep.py
+++ b/lldb/packages/Python/lldbsuite/test/dosep.py
@@ -1469,7 +1469,11 @@ def rerun_tests(test_subdir, tests_for_rerun, dotest_argv):
     # Do not update legacy counts, I am getting rid of
     # them so no point adding complicated merge logic here.
     rerun_thread_count = 1
-    rerun_runner_name = default_test_runner_name(rerun_thread_count)
+    # Force the parallel test runner to choose a multi-worker strategy.
+    rerun_runner_name = default_test_runner_name(rerun_thread_count + 1)
+    print("rerun will use the '{}' test runner strategy".format(
+        rerun_runner_name))
+
     runner_strategies_by_name = get_test_runner_strategies(rerun_thread_count)
     rerun_runner_func = runner_strategies_by_name[
         rerun_runner_name]