Jul 10 - Add test suite

tests/test_sla.py

@@ -0,0 +1,77 @@
+"""
+Tests for the SLA engine (app/utils/sla.py).
+
+sla_status/deadline/hours_remaining read only .status, .severity, .reported_at,
+so a lightweight stand-in object is enough — no DB or app context needed. Time
+is controlled by positioning reported_at relative to now_eastern().
+"""
+from datetime import timedelta
+from types import SimpleNamespace
+
+import pytest
+
+from app.utils.sla import (
+    sla_status, sla_deadline, sla_hours_remaining, SLA_HOURS, AT_RISK_THRESHOLD,
+)
+from app.utils.time_utils import now_eastern
+
+
+def issue(severity='high', status='open', hours_ago=0):
+    return SimpleNamespace(
+        severity=severity,
+        status=status,
+        reported_at=now_eastern() - timedelta(hours=hours_ago),
+    )
+
+
+def test_resolved_issue_has_no_sla():
+    assert sla_status(issue(status='resolved', hours_ago=999)) is None
+
+
+def test_unknown_severity_returns_none():
+    assert sla_status(issue(severity='nonsense', hours_ago=1)) is None
+
+
+def test_fresh_issue_is_ok():
+    # high = 24h window, at-risk at 18h; 1h in is comfortably OK
+    assert sla_status(issue(severity='high', hours_ago=1)) == 'ok'
+
+
+def test_issue_past_at_risk_threshold():
+    # high at-risk at 18h; 20h in is at_risk but not yet breached (24h)
+    assert sla_status(issue(severity='high', hours_ago=20)) == 'at_risk'
+
+
+def test_issue_past_deadline_is_breached():
+    assert sla_status(issue(severity='high', hours_ago=25)) == 'breached'
+
+
+@pytest.mark.parametrize('severity', list(SLA_HOURS.keys()))
+def test_at_risk_boundary_for_each_severity(severity):
+    window = SLA_HOURS[severity]
+    # Just past the at-risk fraction, still before the deadline.
+    at_risk_hours = window * AT_RISK_THRESHOLD
+    assert sla_status(issue(severity=severity, hours_ago=at_risk_hours + 0.1)) == 'at_risk'
+    # Just before the at-risk fraction is still OK.
+    assert sla_status(issue(severity=severity, hours_ago=at_risk_hours - 0.5)) == 'ok'
+
+
+def test_deadline_is_reported_at_plus_window():
+    iss = issue(severity='medium', hours_ago=0)
+    expected = iss.reported_at + timedelta(hours=SLA_HOURS['medium'])
+    assert sla_deadline(iss) == expected
+
+
+def test_hours_remaining_positive_when_within_window():
+    remaining = sla_hours_remaining(issue(severity='critical', hours_ago=1))
+    # critical window is 4h; ~3h should remain
+    assert 2.5 < remaining < 3.5
+
+
+def test_hours_remaining_negative_when_overdue():
+    remaining = sla_hours_remaining(issue(severity='critical', hours_ago=6))
+    assert remaining < 0
+
+
+def test_hours_remaining_none_for_resolved():
+    assert sla_hours_remaining(issue(status='resolved', hours_ago=1)) is None