Add ASA pre-transfer free-space check (NAPPS-1087)

[jtdub]

Summary

• Implements the fail-open pre-transfer free-space check on Cisco ASA using the seam added in NAPPS-1091 (PR Add EOS pre-transfer free-space check (NAPPS-1091) #370), so OS-image transfers fail fast when disk0: lacks room instead of half-writing flash.
• ASADevice._get_free_space parses the (N bytes free) trailer from dir output; file_copy calls _check_free_space(os.path.getsize(src)) before any SCP transfer; remote_file_copy calls _pre_transfer_space_check inside the existing not verify_file block so the check only fires when a transfer would actually happen.
• Unit tests cover the dir-trailer parse, the missing-trailer raise, file_copy raising before SCP, remote_file_copy raising before any copy command, and the fail-open path. Integration tests mirror the EOS pattern for manual lab runs.

NAPPS-1087

Test plan

• poetry run pytest tests/unit/test_devices/test_asa_device.py — all 143 pass.
• poetry run pytest tests/unit — all 659 pass.
• poetry run ruff check pyntc tests — clean.
• Lab run: poetry run pytest tests/integration/test_asa_device.py -v with ASA_HOST / ASA_USER / ASA_PASS / ASA_SECRET + protocol URLs + FILE_CHECKSUM / FILE_SIZE / FILE_SIZE_UNIT set — verifies the probe, the oversized reject, and the fail-open path end-to-end.

🤖 Generated with Claude Code

[jtdub]

% source .env && poetry run pytest tests/integration/test_asa_device.py           
========================================================= test session starts =========================================================
platform darwin -- Python 3.12.11, pytest-9.0.3, pluggy-1.6.0 -- /Users/jameswilliams/Library/Caches/pypoetry/virtualenvs/pyntc-gs002iVE-py3.12/bin/python
cachedir: .pytest_cache
rootdir: /Users/jameswilliams/Documents/code/pyntc
configfile: pyproject.toml
plugins: f5-sdk-3.0.21, requests-mock-1.12.1
collected 16 items                                                                                                                    

tests/integration/test_asa_device.py::test_device_connects PASSED                                                               [  6%]
tests/integration/test_asa_device.py::test_check_file_exists_false PASSED                                                       [ 12%]
tests/integration/test_asa_device.py::test_get_remote_checksum_after_exists PASSED                                              [ 18%]
tests/integration/test_asa_device.py::test_remote_file_copy_ftp PASSED                                                          [ 25%]
tests/integration/test_asa_device.py::test_remote_file_copy_tftp PASSED                                                         [ 31%]
tests/integration/test_asa_device.py::test_remote_file_copy_scp PASSED                                                          [ 37%]
tests/integration/test_asa_device.py::test_remote_file_copy_http PASSED                                                         [ 43%]
tests/integration/test_asa_device.py::test_remote_file_copy_https PASSED                                                        [ 50%]
tests/integration/test_asa_device.py::test_verify_file_after_copy PASSED                                                        [ 56%]
tests/integration/test_asa_device.py::test_get_free_space_returns_positive_int PASSED                                           [ 62%]
tests/integration/test_asa_device.py::test_check_free_space_succeeds_for_small_request PASSED                                   [ 68%]
tests/integration/test_asa_device.py::test_check_free_space_raises_when_required_exceeds_free PASSED                            [ 75%]
tests/integration/test_asa_device.py::test_file_size_unit_conversion_matches_device_free_space PASSED                           [ 81%]
tests/integration/test_asa_device.py::test_remote_file_copy_rejects_oversized_transfer PASSED                                   [ 87%]
tests/integration/test_asa_device.py::test_remote_file_copy_accepts_declared_size_within_free_space PASSED                      [ 93%]
tests/integration/test_asa_device.py::test_remote_file_copy_skips_space_check_when_file_size_omitted PASSED                     [100%]

=================================================== 16 passed in 108.52s (0:01:48) ====================================================

[mattmiller87]

This matches what we were doing in EOS, IOS, NXOS. ASA seems almost identical with the "dir" command output.