bpo-34279, regrtest: Issue a warning if no tests have been executed (GH-10150)

Lib/test/test_regrtest.py

@@ -351,11 +351,20 @@ class BaseTestCase(unittest.TestCase):
         self.tmptestdir = tempfile.mkdtemp()
         self.addCleanup(support.rmtree, self.tmptestdir)
 
-    def create_test(self, name=None, code=''):
+    def create_test(self, name=None, code=None):
         if not name:
             name = 'noop%s' % BaseTestCase.TEST_UNIQUE_ID
             BaseTestCase.TEST_UNIQUE_ID += 1
 
+        if code is None:
+            code = textwrap.dedent("""
+                    import unittest
+
+                    class Tests(unittest.TestCase):
+                        def test_empty_test(self):
+                            pass
+                """)
+
         # test_regrtest cannot be run twice in parallel because
         # of setUp() and create_test()
         name = self.TESTNAME_PREFIX + name
@@ -390,7 +399,7 @@ class BaseTestCase(unittest.TestCase):
 
     def check_executed_tests(self, output, tests, skipped=(), failed=(),
                              env_changed=(), omitted=(),
-                             rerun=(),
+                             rerun=(), no_test_ran=(),
                              randomize=False, interrupted=False,
                              fail_env_changed=False):
         if isinstance(tests, str):
@@ -405,6 +414,8 @@ class BaseTestCase(unittest.TestCase):
             omitted = [omitted]
         if isinstance(rerun, str):
             rerun = [rerun]
+        if isinstance(no_test_ran, str):
+            no_test_ran = [no_test_ran]
 
         executed = self.parse_executed_tests(output)
         if randomize:
@@ -447,8 +458,12 @@ class BaseTestCase(unittest.TestCase):
                 regex = "Re-running test %r in verbose mode" % name
                 self.check_line(output, regex)
 
+        if no_test_ran:
+            regex = list_regex('%s test%s run no tests', no_test_ran)
+            self.check_line(output, regex)
+
         good = (len(tests) - len(skipped) - len(failed)
-                - len(omitted) - len(env_changed))
+                - len(omitted) - len(env_changed) - len(no_test_ran))
         if good:
             regex = r'%s test%s OK\.$' % (good, plural(good))
             if not skipped and not failed and good > 1:
@@ -465,12 +480,16 @@ class BaseTestCase(unittest.TestCase):
             result.append('ENV CHANGED')
         if interrupted:
             result.append('INTERRUPTED')
-        if not result:
+        if not any((good, result, failed, interrupted, skipped,
+                    env_changed, fail_env_changed)):
+            result.append("NO TEST RUN")
+        elif not result:
             result.append('SUCCESS')
         result = ', '.join(result)
         if rerun:
             self.check_line(output, 'Tests result: %s' % result)
             result = 'FAILURE then %s' % result
+
         self.check_line(output, 'Tests result: %s' % result)
 
     def parse_random_seed(self, output):
@@ -649,7 +668,14 @@ class ArgsTestCase(BaseTestCase):
         # test -u command line option
         tests = {}
         for resource in ('audio', 'network'):
-            code = 'from test import support\nsupport.requires(%r)' % resource
+            code = textwrap.dedent("""
+                        from test import support; support.requires(%r)
+                        import unittest
+                        class PassingTest(unittest.TestCase):
+                            def test_pass(self):
+                                pass
+                    """ % resource)
+
             tests[resource] = self.create_test(resource, code)
         test_names = sorted(tests.values())
 
@@ -978,6 +1004,56 @@ class ArgsTestCase(BaseTestCase):
         output = self.run_tests("-w", testname, exitcode=2)
         self.check_executed_tests(output, [testname],
                                   failed=testname, rerun=testname)
+    def test_no_tests_ran(self):
+        code = textwrap.dedent("""
+            import unittest
+
+            class Tests(unittest.TestCase):
+                def test_bug(self):
+                    pass
+        """)
+        testname = self.create_test(code=code)
+
+        output = self.run_tests(testname, "-m", "nosuchtest", exitcode=0)
+        self.check_executed_tests(output, [testname], no_test_ran=testname)
+
+    def test_no_tests_ran_multiple_tests_nonexistent(self):
+        code = textwrap.dedent("""
+            import unittest
+
+            class Tests(unittest.TestCase):
+                def test_bug(self):
+                    pass
+        """)
+        testname = self.create_test(code=code)
+        testname2 = self.create_test(code=code)
+
+        output = self.run_tests(testname, testname2, "-m", "nosuchtest", exitcode=0)
+        self.check_executed_tests(output, [testname, testname2],
+                                  no_test_ran=[testname, testname2])
+
+    def test_no_test_ran_some_test_exist_some_not(self):
+        code = textwrap.dedent("""
+            import unittest
+
+            class Tests(unittest.TestCase):
+                def test_bug(self):
+                    pass
+        """)
+        testname = self.create_test(code=code)
+        other_code = textwrap.dedent("""
+            import unittest
+
+            class Tests(unittest.TestCase):
+                def test_other_bug(self):
+                    pass
+        """)
+        testname2 = self.create_test(code=other_code)
+
+        output = self.run_tests(testname, testname2, "-m", "nosuchtest",
+                                "-m", "test_other_bug", exitcode=0)
+        self.check_executed_tests(output, [testname, testname2],
+                                  no_test_ran=[testname])
 
 
 class TestUtils(unittest.TestCase):