Add a helpful error message to let people know when they've specified named_parameters and forgotten to add names to their parameter tuples rather than crashing later with something obscure.

PiperOrigin-RevId: 280698220
Change-Id: I02cc1eecc3f3310acd0b5ad30f065d6aab240c9d

1 files changed, 4 insertions, 0 deletions

diff --git a/absl/testing/parameterized.py b/absl/testing/parameterized.py
index a7cc88b..b67aaeb 100755
--- a/absl/testing/parameterized.py
+++ b/absl/testing/parameterized.py
@@ -281,6 +281,10 @@ class _ParameterizedTestIter(object):
           testcase_params = {k: v for k, v in six.iteritems(testcase_params)
                              if k != _NAMED_DICT_KEY}
         elif _non_string_or_bytes_iterable(testcase_params):
+          if not isinstance(testcase_params[0], six.string_types):
+            raise RuntimeError(
+                'The first element of named test parameters is the test name '
+                'suffix and must be a string')
           testcase_name = testcase_params[0]
           testcase_params = testcase_params[1:]
         else: