Add --test-show-all-batch-targets to expose all targets in batched pytest

docs/notes/2.32.x.md

@@ -78,6 +78,10 @@ The `find-links` automatically injected by `pants.backend.plugin_development` is
 
 Fixed inverted logic when setting noninteractive_process_output to only log failures.
 
+#### Test
+
+The `test` goal has a new `--show-all-batch-targets` option. When tests are batched via `batch_compatibility_tag`, the default output truncates the list of targets (e.g. `path/to:tests and 3 other files`). Enabling this option shows all target addresses in test result summaries and workunit descriptions, which is useful for understanding exactly which targets are grouped together in each test invocation.
+
 ### Backends
 
 #### Docker

src/python/pants/backend/python/goals/pytest_runner.py

@@ -441,11 +441,14 @@ async def setup_pytest_for_target(
             else:
                 timeout_seconds = timeout
 
-    run_description = request.field_sets[0].address.spec
-    if len(request.field_sets) > 1:
-        run_description = (
-            f"batch of {run_description} and {len(request.field_sets) - 1} other files"
-        )
+    if test_subsystem.show_all_batch_targets and len(request.field_sets) > 1:
+        run_description = ", ".join(fs.address.spec for fs in request.field_sets)
+    else:
+        run_description = request.field_sets[0].address.spec
+        if len(request.field_sets) > 1:
+            run_description = (
+                f"batch of {run_description} and {len(request.field_sets) - 1} other files"
+            )
     process = await setup_venv_pex_process(
         VenvPexProcess(
             pytest_runner_pex,
@@ -533,11 +536,14 @@ async def run_python_tests(
     last_result = results.last
 
     def warning_description() -> str:
-        description = batch.elements[0].address.spec
-        if len(batch.elements) > 1:
-            description = (
-                f"batch containing {description} and {len(batch.elements) - 1} other files"
-            )
+        if test_subsystem.show_all_batch_targets and len(batch.elements) > 1:
+            description = ", ".join(fs.address.spec for fs in batch.elements)
+        else:
+            description = batch.elements[0].address.spec
+            if len(batch.elements) > 1:
+                description = (
+                    f"batch containing {description} and {len(batch.elements) - 1} other files"
+                )
         if batch.partition_metadata.description:
             description = f"{description} ({batch.partition_metadata.description})"
         return description

src/python/pants/core/goals/test.py

@@ -739,6 +739,23 @@ def default_process_cache_scope(self) -> ProcessCacheScope:
             """
         ),
     )
+    show_all_batch_targets = BoolOption(
+        default=False,
+        help=softwrap(
+            """
+            When tests are batched via `batch_compatibility_tag`, show all target addresses in
+            the batch in test result summaries, workunit descriptions, and warning messages.
+
+            By default, batched test descriptions are truncated to show only the first target
+            address (e.g. "path/to:tests and 3 other files"). When this option is enabled, all
+            target addresses in the batch are listed (e.g.
+            "path/to:tests, path/to:tests2, path/to:tests3, path/to:tests4").
+
+            This is useful for CI environments where you need to know exactly which targets
+            are grouped together in each test invocation.
+            """
+        ),
+    )
 
     def report_dir(self, distdir: DistDir) -> PurePath:
         return PurePath(self._report_dir.format(distdir=distdir.relpath))
@@ -1024,7 +1041,9 @@ async def run_tests(
             test_result_info[result.addresses[0].spec] = {
                 "source": result.result_metadata.source(run_id).value
             }
-        console.print_stderr(_format_test_summary(result, run_id, console))
+        console.print_stderr(
+            _format_test_summary(result, run_id, console, test_subsystem.show_all_batch_targets)
+        )
 
         if result.extra_output and result.extra_output.files:
             path_prefix = str(distdir.relpath / "test" / result.path_safe_description)
@@ -1121,7 +1140,12 @@ async def run_tests(
 }
 
 
-def _format_test_summary(result: TestResult, run_id: RunId, console: Console) -> str:
+def _format_test_summary(
+    result: TestResult,
+    run_id: RunId,
+    console: Console,
+    show_all_batch_targets: bool = False,
+) -> str:
     """Format the test summary printed to the console."""
     assert result.result_metadata is not None, (
         "Skipped test results should not be outputted in the test summary"
@@ -1164,7 +1188,12 @@ def _format_test_summary(result: TestResult, run_id: RunId, console: Console) ->
         elapsed_secs = total_elapsed_ms / 1000
         elapsed_print = f"in {elapsed_secs:.2f}s"
 
-    return f"{sigil} {result.description} {status}{attempt_msg} {elapsed_print}{source_desc}."
+    if show_all_batch_targets and len(result.addresses) > 1:
+        description = ", ".join(addr.spec for addr in result.addresses)
+    else:
+        description = result.description
+
+    return f"{sigil} {description} {status}{attempt_msg} {elapsed_print}{source_desc}."
 
 
 def _format_test_rerun_command(results: Iterable[TestResult]) -> None | str:

src/python/pants/core/goals/test_test.py

@@ -276,6 +276,7 @@ def run_test_rule(
         shard="",
         batch_size=1,
         show_rerun_command=show_rerun_command,
+        show_all_batch_targets=False,
     )
     debug_adapter_subsystem = create_subsystem(
         DebugAdapterSubsystem,
@@ -341,17 +342,18 @@ def mock_coverage_report_generation(
             ],
             mock_calls={
                 "pants.core.goals.test.partition_tests": mock_partitioner,
-                "pants.core.environments.rules.resolve_single_environment_name": lambda _a: EnvironmentName(
-                    None
+                "pants.core.environments.rules.resolve_single_environment_name": lambda _a: (
+                    EnvironmentName(None)
                 ),
                 "pants.core.goals.test.test_batch_to_debug_request": mock_debug_request,
                 "pants.core.goals.test.test_batch_to_debug_adapter_request": mock_debug_request,
                 "pants.core.goals.test.run_test_batch": mock_test_partition,
                 "pants.core.goals.test.create_coverage_report": mock_coverage_report_generation,
                 "pants.engine.internals.specs_rules.find_valid_field_sets_for_target_roots": mock_find_valid_field_sets,
                 "pants.engine.intrinsics.merge_digests": lambda _: EMPTY_DIGEST,
-                "pants.engine.intrinsics._interactive_process": lambda _p,
-                _e: InteractiveProcessResult(0),
+                "pants.engine.intrinsics._interactive_process": lambda _p, _e: (
+                    InteractiveProcessResult(0)
+                ),
             },
             union_membership=union_membership,
             # We don't want temporary warnings to interfere with our expected output.