[Fuzz task steps duration] Add testcase file removal duration metric

src/clusterfuzz/_internal/bot/tasks/utasks/fuzz_task.py

@@ -2284,8 +2284,9 @@ def run(self):
     # Delete the fuzzed testcases. This was once explicitly needed since some
     # testcases resided on NFS and would otherwise be left forever. Now it's
     # unclear if needed but it is kept because it is not harmful.
-    for testcase_file_path in testcase_file_paths:
-      shell.remove_file(testcase_file_path)
+    with self.steps_time_tracker.track('remove_testcase_file'):
+      for testcase_file_path in testcase_file_paths:
+        shell.remove_file(testcase_file_path)
 
     # TODO(dylanj): Handle cases where the blackbox fuzzer executes multiple
     # logical testcases per test file and we'd like to factor that multiplier

src/clusterfuzz/_internal/metrics/fuzzer_stats.py

@@ -66,6 +66,11 @@
         'type': 'INTERVAL',
         'mode': 'NULLABLE',
     },
+    {
+        'name': 'remove_testcase_file',
+        'type': 'INTERVAL',
+        'mode': 'NULLABLE',
+    },
 ]
 JOB_RUN_SCHEMA = {
     'fields': [

src/clusterfuzz/_internal/tests/core/bot/tasks/utasks/fuzz_task_test.py

@@ -1841,6 +1841,53 @@ def test_utask_main_blackbox_fuzzer_no_crashes(
     })
     self.assertEqual(1, parse_dist.count)
 
+  @mock.patch(
+      'clusterfuzz._internal.bot.tasks.utasks.fuzz_task.FuzzingSession.generate_blackbox_testcases'
+  )
+  def test_utask_main_remove_testcase_file(self,
+                                           mock_generate_blackbox_testcases):
+    """Test that deleting the fuzzed testcases is tracked."""
+    self._setup_utask_env()
+    fuzzer = self._create_test_fuzzer()
+    uworker_input = self._create_blackbox_uworker_input(fuzzer)
+
+    testcase_file_paths = ['/tests/0', '/tests/1', '/tests/2']
+    for path in testcase_file_paths:
+      self.fs.create_file(path, contents='testcase')
+    mock_generate_blackbox_testcases.return_value = (
+        fuzz_task.GenerateBlackboxTestcasesResult(
+            True, testcase_file_paths, {'fuzzer_binary_name': fuzzer.name}))
+
+    actual = fuzz_task.utask_main(uworker_input)
+
+    for path in testcase_file_paths:
+      self.assertFalse(os.path.exists(path))
+    self.assertGreater(
+        actual.fuzz_task_output.steps_duration['remove_testcase_file']
+        .ToTimedelta().total_seconds(), 0)
+    dist = monitoring_metrics.FUZZ_TASK_STEPS_DURATION.get({
+        'fuzzer': fuzzer.name,
+        'job': 'asan_test',
+        'platform': environment.platform(),
+        'runtime': environment.get_runtime().value,
+        'step': 'remove_testcase_file',
+        'success': True,
+    })
+    self.assertEqual(1, dist.count)
+    self.assertGreater(dist.sum, 0)
+
+  def _create_blackbox_uworker_input(self, fuzzer):
+    """Creates a uworker input for a blackbox fuzzing utask_main run."""
+    fuzz_task_input = uworker_msg_pb2.FuzzTaskInput()
+    setup_input = uworker_msg_pb2.SetupInput(
+        fuzzer_name=fuzzer.name, fuzzer=uworker_io.entity_to_protobuf(fuzzer))
+    return uworker_msg_pb2.Input(
+        fuzzer_name=fuzzer.name,
+        job_type='asan_test',
+        fuzz_task_input=fuzz_task_input,
+        setup_input=setup_input,
+        uworker_env={'FUZZ_TEST_TIMEOUT': '10'})
+
 
 class DoBlackboxFuzzingDeferredLoggingTest(fake_filesystem_unittest.TestCase):
   """do_blackbox_fuzzing deferred log upload unit tests without datastore dependency."""