feat(analysis): _detect_gaps su timestamp consecutivi (> 20 min)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/cerbero_bite/analysis/data_audit.py

@@ -124,3 +124,19 @@ def _expected_ticks(since: datetime, until: datetime) -> int:
     # aligned multiples and would mis-count non-aligned spans.
     span_seconds = (until - first_tick).total_seconds()
     return math.ceil(span_seconds / (_TICK_INTERVAL_MIN * 60))
+
+
+def _detect_gaps(timestamps: list[datetime]) -> tuple[GapRecord, ...]:
+    """Return gaps where consecutive timestamps differ by > threshold."""
+    out: list[GapRecord] = []
+    for prev, nxt in zip(timestamps, timestamps[1:], strict=False):
+        delta_min = int((nxt - prev).total_seconds() // 60)
+        if delta_min > _GAP_THRESHOLD_MIN:
+            out.append(
+                GapRecord(
+                    prev_timestamp=prev,
+                    next_timestamp=nxt,
+                    gap_minutes=delta_min,
+                )
+            )
+    return tuple(out)

tests/unit/test_data_audit.py

@@ -43,3 +43,37 @@ def test_expected_ticks_exact_quarter_boundary_is_excluded() -> None:
     until = datetime(2026, 5, 12, 12, 45, tzinfo=UTC)
     # Ticks at 12:00, 12:15, 12:30 → 3 (12:45 excluded)
     assert _expected_ticks(since, until) == 3
+
+
+from cerbero_bite.analysis.data_audit import _detect_gaps  # noqa: PLC2701
+
+
+def test_detect_gaps_returns_empty_when_no_gap() -> None:
+    ts = [
+        datetime(2026, 5, 12, 12, 0, tzinfo=UTC),
+        datetime(2026, 5, 12, 12, 15, tzinfo=UTC),
+        datetime(2026, 5, 12, 12, 30, tzinfo=UTC),
+    ]
+    assert _detect_gaps(ts) == ()
+
+
+def test_detect_gaps_flags_above_threshold() -> None:
+    ts = [
+        datetime(2026, 5, 12, 12, 0, tzinfo=UTC),
+        datetime(2026, 5, 12, 12, 45, tzinfo=UTC),  # 45-min gap
+        datetime(2026, 5, 12, 13, 0, tzinfo=UTC),
+    ]
+    gaps = _detect_gaps(ts)
+    assert len(gaps) == 1
+    assert gaps[0].gap_minutes == 45
+    assert gaps[0].prev_timestamp == ts[0]
+    assert gaps[0].next_timestamp == ts[1]
+
+
+def test_detect_gaps_ignores_threshold_boundary() -> None:
+    # 20-min gap is exactly the threshold → NOT flagged (strict >)
+    ts = [
+        datetime(2026, 5, 12, 12, 0, tzinfo=UTC),
+        datetime(2026, 5, 12, 12, 20, tzinfo=UTC),
+    ]
+    assert _detect_gaps(ts) == ()