mcaxl/tests/test_css_impact.py

"""Hamilton review MAJOR #3: find_devices_using_css must surface partial failures.

The function is per-category resilient by design — if one schema query fails,
the others still produce results. But the top-level summary previously hid
that some categories errored out: `total_returned` and `any_truncated` only
reflected the SUCCESSFUL categories. An LLM consuming "47 references, low
impact" wouldn't know that 5 categories errored and the real number is
likely much higher.

After the fix: the response includes `complete: bool`, `categories_with_errors`,
and `error_categories`, so an LLM (or human auditor) can see the partial-failure
state and act on it.
"""

import pytest

from mcp_cucm_axl.route_plan import find_devices_using_css


class FakeAxlClient:
    """Minimal stand-in for AxlClient that lets us simulate per-query failures.

    Returns a fake CSS pkid for the lookup query, then either a single fake row
    or an exception based on substring matching.
    """

    def __init__(self, error_on_columns: list[str] | None = None):
        self.error_on_columns = error_on_columns or []
        self.queries: list[str] = []

    def execute_sql_query(self, sql: str) -> dict:
        self.queries.append(sql)
        # The CSS lookup query — return a fake pkid
        if "callingsearchspace WHERE name" in sql:
            return {"row_count": 1, "rows": [{"pkid": "fake-css-pkid"}]}
        # Any query referencing an "error trigger" column → simulate failure
        for trigger in self.error_on_columns:
            if trigger in sql:
                raise RuntimeError(f"simulated cluster failure on {trigger}")
        # Otherwise return one fake reference row so the category isn't empty
        return {
            "row_count": 1,
            "rows": [{"name": "FakeRef", "context": "FakePart", "description": "fake"}],
        }


def test_no_errors_reports_complete():
    """Baseline: when every category succeeds, complete=True and no error fields populated."""
    client = FakeAxlClient()
    result = find_devices_using_css(client, "Some-CSS")
    assert result["complete"] is True
    assert result["categories_with_errors"] == 0
    assert result["error_categories"] == []
    # And total_returned reflects the successful categories
    assert result["total_returned"] >= 1


def test_one_errored_category_marks_incomplete():
    """The audit-trust failure mode: one category errors out and the summary lies.
    Fix: complete=False, categories_with_errors >= 1.
    """
    client = FakeAxlClient(error_on_columns=["fkcallingsearchspace_cgpnunknown"])
    result = find_devices_using_css(client, "Some-CSS")
    assert result["complete"] is False, (
        "complete must be False when any category errored"
    )
    assert result["categories_with_errors"] >= 1
    assert "device_cgpn_unknown_css" in result["error_categories"]


def test_multiple_errors_all_listed():
    """All errored categories must be enumerated in error_categories."""
    client = FakeAxlClient(
        error_on_columns=[
            "fkcallingsearchspace_cgpnunknown",
            "fkcallingsearchspace_reroute",
            "fkcallingsearchspace_pilotqueuefull",
        ]
    )
    result = find_devices_using_css(client, "Some-CSS")
    assert result["complete"] is False
    assert result["categories_with_errors"] == 3
    assert set(result["error_categories"]) == {
        "device_cgpn_unknown_css",
        "device_reroute_css",
        "huntpilot_queue_full_css",
    }


def test_total_returned_does_not_include_error_categories():
    """An errored category contributes 0 to total_returned (correct behavior).
    What's NEW: the response also flags that the count is partial.
    """
    client = FakeAxlClient(error_on_columns=["fkcallingsearchspace_cgpnunknown"])
    result = find_devices_using_css(client, "Some-CSS")
    # The count itself is unchanged from before — what's new is the warning
    assert result["complete"] is False
    # The error category has no rows in references_by_category
    err_cat = result["references_by_category"].get("device_cgpn_unknown_css", {})
    assert "error" in err_cat


def test_css_not_found_returns_error_not_partial():
    """If the CSS lookup itself fails (CSS doesn't exist), we return the
    'not found' error early, NOT a partial-failure response. Distinct
    failure modes deserve distinct shapes.
    """

    class CssNotFoundClient:
        def execute_sql_query(self, sql):
            if "callingsearchspace WHERE name" in sql:
                return {"row_count": 0, "rows": []}
            return {"row_count": 1, "rows": [{}]}

    result = find_devices_using_css(CssNotFoundClient(), "Nonexistent-CSS")
    assert "error" in result
    assert "complete" not in result, (
        "CSS-not-found is a hard error; we shouldn't dress it up as partial"
    )