feat(test-cli): append pytest command to Github Actions job summary

When `$GITHUB_STEP_SUMMARY` is set, `PytestRunner` now also appends the
resolved `pytest ...` invocation to the step summary as a fenced code
block, so it can be copied from the Actions "Summary" panel of a failing
run instead of scrolling through the log. Outside Github Actions the
env var is unset and behavior is unchanged.

Author: danceratopz

docs/dev/test_actions_locally.md

@@ -120,4 +120,4 @@ The pytest-based CLIs (`fill`, `execute`, ...) print the resolved `pytest ...` i
 Executing: pytest ...
 ```
 
-Copy this line verbatim from the failing Github Actions log and run it locally to reproduce the exact command, including all plugin and marker arguments injected by the CLI.
+When run under Github Actions, the same command is also appended to the job summary (via `$GITHUB_STEP_SUMMARY`), so it can be copied directly from the "Summary" panel of the failing run without scrolling through the log.

packages/testing/src/execution_testing/cli/pytest_commands/base.py

@@ -88,6 +88,12 @@ def run_single(self, execution: PytestExecution) -> int:
         if self._is_verbose(execution.args) or "CI" in os.environ:
             pytest_cmd = f"pytest {' '.join(pytest_args)}"
             self.error_console.print(f"Executing: [bold]{pytest_cmd}[/bold]")
+            summary_path = os.environ.get("GITHUB_STEP_SUMMARY")
+            if summary_path:
+                with Path(summary_path).open("a") as summary:
+                    summary.write(
+                        f"### Executing\n\n```bash\n{pytest_cmd}\n```\n\n"
+                    )
 
         return pytest.main(pytest_args)