#128: support matching substring and glob patterns using bazel's `--test_filter=` flag (Python 3.7+ only).

Previously, the `--test_filter=` arguments are passed to Python's unittest as positional arguments. This only matches by class or method's full names.

After this, `--test_filter=` has the same meaning as unittest's `-k` flag: https://docs.python.org/3/library/unittest.html#cmdoption-unittest-k

One notable behavior difference: previously if the filter doesn't match any tests, the test would fail; now it doesn't fail.

This also makes filtering `absltest.parameterized` tests significantly more user friendly.

This change is only for Python 3.7+.

PiperOrigin-RevId: 401582298
Change-Id: I074e9283706fe9c88a8dbb392084fb6548cebc6f

5 files changed, 101 insertions, 7 deletions

diff --git a/absl/CHANGELOG.md b/absl/CHANGELOG.md
index 5e2506f..55b5f0f 100644
--- a/absl/CHANGELOG.md
+++ b/absl/CHANGELOG.md
@@ -6,7 +6,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com).
 
 ## Unreleased
 
-Nothing notable unreleased.
+### Changed
+
+*   (testing) #128: When running bazel with its `--test_filter=` flag, it now
+    treats the filters as `unittest`'s `-k` flag in Python 3.7+.
 
 ## 0.14.1 (2021-09-30)
 
diff --git a/absl/testing/BUILD b/absl/testing/BUILD
index 609d626..14c9a5f 100644
--- a/absl/testing/BUILD
+++ b/absl/testing/BUILD
@@ -106,7 +106,7 @@ py_library(
 
 py_test(
     name = "tests/absltest_filtering_test",
-    size = "small",
+    size = "medium",
     srcs = ["tests/absltest_filtering_test.py"],
     data = [":tests/absltest_filtering_test_helper"],
     python_version = "PY3",
@@ -128,6 +128,7 @@ py_binary(
     srcs_version = "PY3",
     deps = [
         ":absltest",
+        ":parameterized",
         "//absl:app",
     ],
 )
diff --git a/absl/testing/absltest.py b/absl/testing/absltest.py
index a6a8a8c..a79cde7 100644
--- a/absl/testing/absltest.py
+++ b/absl/testing/absltest.py
@@ -2336,8 +2336,12 @@ def _setup_filtering(argv):
   The following environment variable is used in this method:
 
     TESTBRIDGE_TEST_ONLY: string, if set, is forwarded to the unittest
-      framework to use as a test filter. Its value is split with shlex
-      before being passed as positional arguments on argv.
+      framework to use as a test filter. Its value is split with shlex, then:
+      1. On Python 3.6 and before, split values are passed as positional
+         arguments on argv.
+      2. On Python 3.7+, split values are passed to unittest's `-k` flag. Tests
+         are matched by glob patterns or substring. See
+         https://docs.python.org/3/library/unittest.html#cmdoption-unittest-k
 
   Args:
     argv: the argv to mutate in-place.
@@ -2346,7 +2350,11 @@ def _setup_filtering(argv):
   if argv is None or not test_filter:
     return
 
-  argv[1:1] = shlex.split(test_filter)
+  filters = shlex.split(test_filter)
+  if sys.version_info[:2] >= (3, 7):
+    filters = ['-k=' + test_filter for test_filter in filters]
+
+  argv[1:1] = filters
 
 
 def _setup_test_runner_fail_fast(argv):
diff --git a/absl/testing/tests/absltest_filtering_test.py b/absl/testing/tests/absltest_filtering_test.py
index 63e3915..30a81f6 100644
--- a/absl/testing/tests/absltest_filtering_test.py
+++ b/absl/testing/tests/absltest_filtering_test.py
@@ -18,6 +18,7 @@ from __future__ import division
 from __future__ import print_function
 
 import subprocess
+import sys
 
 from absl import logging
 from absl.testing import _bazelize_command
@@ -63,7 +64,12 @@ class TestFilteringTest(absltest.TestCase):
       if use_env_variable:
         env['TESTBRIDGE_TEST_ONLY'] = test_filter
       elif test_filter:
-        additional_args.extend(test_filter.split(' '))
+        if sys.version_info[:2] >= (3, 7):
+          # The -k flags are passed as positional arguments to absl.flags.
+          additional_args.append('--')
+          additional_args.extend(['-k=' + f for f in test_filter.split(' ')])
+        else:
+          additional_args.extend(test_filter.split(' '))
 
     proc = subprocess.Popen(
         args=([_bazelize_command.get_executable_path(self._test_name)] +
@@ -115,12 +121,72 @@ class TestFilteringTest(absltest.TestCase):
     self.assertIn('class B test C', out)
     self.assertNotIn('class B test A', out)
 
-  def test_not_found_filters(self, use_env_variable, use_app_run):
+  @absltest.skipIf(
+      sys.version_info[:2] < (3, 7),
+      'Only Python 3.7+ does glob and substring matching.')
+  def test_substring(self, use_env_variable, use_app_run):
+    out, exit_code = self._run_filtered(
+        'testA', use_env_variable, use_app_run)
+    self.assertEqual(0, exit_code)
+    self.assertIn('Ran 2 tests', out)
+    self.assertIn('ClassA.testA', out)
+    self.assertIn('ClassB.testA', out)
+
+  @absltest.skipIf(
+      sys.version_info[:2] < (3, 7),
+      'Only Python 3.7+ does glob and substring matching.')
+  def test_glob_pattern(self, use_env_variable, use_app_run):
+    out, exit_code = self._run_filtered(
+        '__main__.Class*.testA', use_env_variable, use_app_run)
+    self.assertEqual(0, exit_code)
+    self.assertIn('Ran 2 tests', out)
+    self.assertIn('ClassA.testA', out)
+    self.assertIn('ClassB.testA', out)
+
+  @absltest.skipIf(
+      sys.version_info[:2] >= (3, 7),
+      "Python 3.7+ uses unittest's -k flag and doesn't fail if no tests match.")
+  def test_not_found_filters_py36(self, use_env_variable, use_app_run):
     out, exit_code = self._run_filtered('NotExistedClass.not_existed_method',
                                         use_env_variable, use_app_run)
     self.assertEqual(1, exit_code)
     self.assertIn("has no attribute 'NotExistedClass'", out)
 
+  @absltest.skipIf(
+      sys.version_info[:2] < (3, 7),
+      'Python 3.6 passes the filter as positional arguments and fails if no '
+      'tests match.'
+  )
+  def test_not_found_filters_py37(self, use_env_variable, use_app_run):
+    out, exit_code = self._run_filtered('NotExistedClass.not_existed_method',
+                                        use_env_variable, use_app_run)
+    self.assertEqual(0, exit_code)
+    self.assertIn('Ran 0 tests', out)
+
+  @absltest.skipIf(
+      sys.version_info[:2] < (3, 7),
+      'Python 3.6 passes the filter as positional arguments and matches by name'
+  )
+  def test_parameterized_unnamed(self, use_env_variable, use_app_run):
+    out, exit_code = self._run_filtered('ParameterizedTest.test_unnamed',
+                                        use_env_variable, use_app_run)
+    self.assertEqual(0, exit_code)
+    self.assertIn('Ran 2 tests', out)
+    self.assertIn('parameterized unnamed 1', out)
+    self.assertIn('parameterized unnamed 2', out)
+
+  @absltest.skipIf(
+      sys.version_info[:2] < (3, 7),
+      'Python 3.6 passes the filter as positional arguments and matches by name'
+  )
+  def test_parameterized_named(self, use_env_variable, use_app_run):
+    out, exit_code = self._run_filtered('ParameterizedTest.test_named',
+                                        use_env_variable, use_app_run)
+    self.assertEqual(0, exit_code)
+    self.assertIn('Ran 2 tests', out)
+    self.assertIn('parameterized named 1', out)
+    self.assertIn('parameterized named 2', out)
+
 
 if __name__ == '__main__':
   absltest.main()
diff --git a/absl/testing/tests/absltest_filtering_test_helper.py b/absl/testing/tests/absltest_filtering_test_helper.py
index 2775a62..2b741ed 100644
--- a/absl/testing/tests/absltest_filtering_test_helper.py
+++ b/absl/testing/tests/absltest_filtering_test_helper.py
@@ -23,6 +23,7 @@ import sys
 
 from absl import app
 from absl.testing import absltest
+from absl.testing import parameterized
 
 
 class ClassA(absltest.TestCase):
@@ -58,6 +59,21 @@ class ClassB(absltest.TestCase):
     self.fail('Force failure')
 
 
+class ParameterizedTest(parameterized.TestCase):
+  """Helper parameterized test case for absltest_filtering_test."""
+
+  @parameterized.parameters([1, 2])
+  def test_unnamed(self, value):
+    sys.stderr.write('\nparameterized unnamed %s' % value)
+
+  @parameterized.named_parameters(
+      ('test1', 1),
+      ('test2', 2),
+  )
+  def test_named(self, value):
+    sys.stderr.write('\nparameterized named %s' % value)
+
+
 def main(argv):
   absltest.main(argv=argv)