refactor(conftest): lift orch fixture into cvs/tests/conftest.py + fix report_plugins JSON-escape regression [AIMVT-172]

[atnair-amd]

Jira: AIMVT-172

Summary

• Lift the canonical orch pytest fixture into a new cvs/tests/conftest.py. Pytest walks the conftest hierarchy upward, so suites under cvs/tests/ pick it up automatically with zero per-suiteboilerplate.
• Delete the module-local orch fixture and its now-unused OrchestratorConfig /OrchestratorFactory imports from cvs/tests/health/rvs_cvs.py; the conftest one takesover.
• Replace a string-form re.sub replacement in cvs/lib/report_plugins.py with a function-form lambda so JSON \n / \t escapes inside data-jsonblob are preserved verbatim. Without this, the rvs_cvs HTML report in container mode renders with an empty results table.

Why

The orch fixture is the single seam between a pytest suite and the orchestrator factory introduced by #135. As transferbench_cvs, agfhc_cvs, and friends migrate off phdl / Pssh (AIMVT-168 through AIMVT-171), every one of them would otherwise copy-paste the same ~15-line fixture body + the same two imports + the same container setup/teardown wiring. Lifting it once keeps that surface single-sourced; subsequent suite migrations become a mechanical phdl → orch rename. The lifted fixture is identical to the original except it gains an explicit CLI-arg guard:

@pytest.fixture(scope="module")
def orch(pytestconfig):
    cluster_file = pytestconfig.getoption("cluster_file")
    config_file = pytestconfig.getoption("config_file")
    if not cluster_file or not config_file:
        pytest.fail("orch fixture requires --cluster_file and --config_file")
    cfg = OrchestratorConfig.from_configs(cluster_file, config_file)
    orch = OrchestratorFactory.create_orchestrator(log, cfg)
    if cfg.orchestrator == "container":
        if not orch.setup_containers():
            pytest.fail(
                f"Failed to launch container : "
                f"{orch.get_container_name(orch.container_config,
orch.container_config['image'])}"
            )
        if not orch.setup_sshd():
            pytest.fail("Failed to setup sshd in container")
    yield orch
    if cfg.orchestrator == "container":
        orch.teardown_containers()

The previous local fixture raised a NoneType deep inside OrchestratorConfig.from_configs when invoked without --cluster_file /--config_file; the explicit pytest.fail(...) turns that into an actionable message at the fixture boundary.

The report_plugins change addresses a latent regression in _update_environment_config_links: the function mutates pytest-html's embedded data-jsonblob dict to inject clickable cluster/config-file links, then re-serializes via re.sub(pattern, replacement_string, html_content). Per the re docs, string-form replacements have backslash escapes processed, which collapses the JSON-encoded \n / \t 2-char escapes into raw 0x0A / 0x09 bytes inside JSON string values, breaking JSON.parse in the browser. Function-form (lambda) replacements skip that processing.

What is NOT changed

• No new CLI options. --cluster_file / --config_file are still registered in cvs/conftest.py:31-53; the new cvs/tests/conftest.py inherits them via pytest's conftest walk.
• No other suite under cvs/tests/ is touched. transferbench_cvs / agfhc_cvs /others are queued under AIMVT-168 through AIMVT-171.
• No L1 doc changes (docs/how-to/run-with-containers.rst, docs/reference/configuration-files/cluster-file.rst, cvs/input/cluster_file/README.md).
• No addfinalizer, no eager get_container_name, no detailed=True / hosts= /exit-code-check additions on orch.exec(...).
• cluster_file / config_file fixtures in rvs_cvs.py:24-31 left alone —cluster_dict / config_dict still consume them.

Verification

• python -m pytest cvs/core/orchestrators/unittests/ cvs/core/runtimes/unittests/ -q — green.
• rg -n '\bdef orch\b|OrchestratorConfig|OrchestratorFactory' cvs/tests/health/rvs_cvs.py — 0 hits.
• cvs run rvs_cvs level-4 on an 8x MI300X node, both orchestrator: baremetal and orchestrator: container —both 2 passed, 6 skipped, HTML reports render cleanly. Run zips (auto-bundles) are attached to AIMVT-172.

Commits

1. 053fe60 test: lift orch fixture into cvs/tests/conftest.py
2. 2e7bcb4 test(rvs_cvs): consume conftest-lifted orch fixture
3. 79cab56 fix(report_plugins): use function-form re.sub replacement to preserve JSON escapes