Fix test runner failures for Python on Windows
diff --git a/tools/run_tests/run_tests.py b/tools/run_tests/run_tests.py
index 1544ff3..c49ee4a 100755
--- a/tools/run_tests/run_tests.py
+++ b/tools/run_tests/run_tests.py
@@ -511,7 +511,7 @@
config.run,
timeout_seconds=5*60,
environ=dict(list(environment.items()) +
- [('GRPC_PYTHON_TESTRUNNER_FILTER', suite_name)]),
+ [('GRPC_PYTHON_TESTRUNNER_FILTER', str(suite_name))]),
shortname='%s.test.%s' % (config.name, suite_name),)
for suite_name in tests_json
for config in self.pythons]