[Tests] Make run_test.py usable without boto3 (#104111)

There is a `HAVE_TEST_SELECTION_TOOLS` conditional, but turns out it does not really work, so fix it by defining all missing prototypes and make it work as single-shard instance

Add lint rule to test stat it would succeed for runnign only test_cuda with released version of PyTorch

Pull Request resolved: https://github.com/pytorch/pytorch/pull/104111
Approved by: https://github.com/clee2000, https://github.com/ZainRizvi

test/run_test.py

@@ -13,7 +13,7 @@ import sys
 import tempfile
 from datetime import datetime
 from distutils.version import LooseVersion
-from typing import Any, cast, Dict, List, Optional
+from typing import Any, cast, Dict, List, Optional, Union
 
 import pkg_resources
 
@@ -52,6 +52,11 @@ try:
 
     HAVE_TEST_SELECTION_TOOLS = True
 except ImportError as e:
+
+    class ShardedTest:
+        pass
+
+    NUM_PROCS = 2
     HAVE_TEST_SELECTION_TOOLS = False
     print(
         f"Unable to import test_selections from tools/testing. Running without test selection stats.... Reason: {e}"
@@ -608,7 +613,7 @@ def run_test(
         and test_module.time is not None
         else None
     )
-    print_to_stderr("Executing {} ... [{}]".format(command, datetime.now()))
+    print_to_stderr(f"Executing {command} ... [{datetime.now()}]")
 
     with open(log_path, "w") as f:
         ret_code = retry_shell(
@@ -978,7 +983,7 @@ def get_pytest_args(
     if not is_cpp_test:
         # C++ tests need to be run with pytest directly, not via python
         pytest_args.extend(["-p", "no:xdist", "--use-pytest"])
-        if not options.continue_through_error:
+        if not options.continue_through_error and HAVE_TEST_SELECTION_TOOLS:
             pytest_args.append(f"--sc={stepcurrent_key}")
     else:
         # Use pytext-dist to run C++ tests in parallel as running them sequentially using run_test
@@ -1424,23 +1429,28 @@ def get_selected_tests(options) -> List[ShardedTest]:
     else:
         print("Found test time stats from artifacts")
 
-    # Do sharding
-    test_file_times_config = test_file_times.get(test_config, {})
-    shards = calculate_shards(
-        num_shards, selected_tests, test_file_times_config, must_serial=must_serial
-    )
-    _, tests_from_shard = shards[which_shard - 1]
-    selected_tests = tests_from_shard
+    if HAVE_TEST_SELECTION_TOOLS:
+        # Do sharding
+        test_file_times_config = test_file_times.get(test_config, {})
+        shards = calculate_shards(
+            num_shards, selected_tests, test_file_times_config, must_serial=must_serial
+        )
+        _, tests_from_shard = shards[which_shard - 1]
+        selected_tests = tests_from_shard
 
     return selected_tests
 
 
-def run_test_module(test: ShardedTest, test_directory: str, options) -> Optional[str]:
+def run_test_module(
+    test: Union[ShardedTest, str], test_directory: str, options
+) -> Optional[str]:
     maybe_set_hip_visible_devies()
 
     # Printing the date here can help diagnose which tests are slow
-    print_to_stderr("Running {} ... [{}]".format(str(test), datetime.now()))
-    handler = CUSTOM_HANDLERS.get(test.name, run_test)
+    print_to_stderr(f"Running {str(test)} ... [{datetime.now()}]")
+    handler = CUSTOM_HANDLERS.get(
+        test.name if isinstance(test, ShardedTest) else test, run_test
+    )
     return_code = handler(test, test_directory, options)
     assert isinstance(return_code, int) and not isinstance(
         return_code, bool
@@ -1468,7 +1478,11 @@ def run_tests(
 
     # parallel = in parallel with other files
     # serial = this file on it's own.  The file might still be run in parallel with itself (ex test_ops)
-    selected_tests_parallel = [x for x in selected_tests if not must_serial(x.name)]
+    selected_tests_parallel = [
+        x
+        for x in selected_tests
+        if not must_serial(x.name if isinstance(x, ShardedTest) else x)
+    ]
     selected_tests_serial = [
         x for x in selected_tests if x not in selected_tests_parallel
     ]
@@ -1602,7 +1616,7 @@ def main():
 
     prioritized_tests = []
     remaining_tests = selected_tests
-    if IS_CI:
+    if IS_CI and HAVE_TEST_SELECTION_TOOLS:
         (prioritized_tests, remaining_tests) = get_reordered_tests(selected_tests)
         log_time_savings(
             selected_tests,