|
| 1 | +""" |
| 2 | +Unit test for retransmission request-slice behavior. |
| 3 | +
|
| 4 | +Reproduces the gap-detection + missing_reporter request-slice logic |
| 5 | +from data.py without needing sockets, Redis, or Docker. |
| 6 | +
|
| 7 | +The request slice uses sorted()[:100] (oldest first) so that gaps |
| 8 | +closest to aging out of the car's 60s ring buffer get priority. |
| 9 | +""" |
| 10 | +import pytest |
| 11 | + |
| 12 | + |
| 13 | +def simulate_gap_detection(seq_stream: list[int]): |
| 14 | + """Replay the base receiver's gap-detection state machine. |
| 15 | +
|
| 16 | + Returns the final (missing_seqs, expected_seq) after processing all seqs. |
| 17 | + This mirrors data.py lines 618-655 exactly. |
| 18 | + """ |
| 19 | + expected_seq = None |
| 20 | + missing_seqs: set[int] = set() |
| 21 | + |
| 22 | + for seq in seq_stream: |
| 23 | + if expected_seq is None: |
| 24 | + expected_seq = seq |
| 25 | + if expected_seq is not None and seq < expected_seq - 1000: |
| 26 | + expected_seq = seq |
| 27 | + missing_seqs.clear() |
| 28 | + if seq > expected_seq: |
| 29 | + for s in range(expected_seq, seq): |
| 30 | + missing_seqs.add(s) |
| 31 | + if len(missing_seqs) > 1000: |
| 32 | + oldest = min(missing_seqs) |
| 33 | + missing_seqs.remove(oldest) |
| 34 | + elif seq < expected_seq: |
| 35 | + if seq in missing_seqs: |
| 36 | + missing_seqs.remove(seq) |
| 37 | + else: |
| 38 | + continue |
| 39 | + expected_seq = max(expected_seq, seq + 1) |
| 40 | + |
| 41 | + return missing_seqs, expected_seq |
| 42 | + |
| 43 | + |
| 44 | +def simulate_request_slice(missing_seqs: set[int]) -> list[int]: |
| 45 | + """The exact line from missing_reporter: sorted(list(missing_seqs))[:100]""" |
| 46 | + return sorted(list(missing_seqs))[:100] |
| 47 | + |
| 48 | + |
| 49 | +class TestOldestFirstRecovery: |
| 50 | + """Verify oldest-first request slice prevents starvation.""" |
| 51 | + |
| 52 | + def test_small_gap_all_requested(self): |
| 53 | + """<=100 missing seqs: everything gets requested.""" |
| 54 | + missing = set(range(10, 60)) |
| 55 | + requested = simulate_request_slice(missing) |
| 56 | + assert set(requested) == missing |
| 57 | + |
| 58 | + def test_large_gap_oldest_requested_first(self): |
| 59 | + """>100 missing: oldest 100 are requested, not newest.""" |
| 60 | + missing = set(range(10, 210)) # 200 missing |
| 61 | + requested = simulate_request_slice(missing) |
| 62 | + |
| 63 | + assert len(requested) == 100 |
| 64 | + assert set(requested) == set(range(10, 110)) |
| 65 | + |
| 66 | + def test_single_burst_self_heals(self): |
| 67 | + """A burst of 200 missing seqs recovers fully in 2 cycles.""" |
| 68 | + missing = set(range(10, 210)) |
| 69 | + |
| 70 | + # Cycle 1: oldest 100 recovered |
| 71 | + requested = simulate_request_slice(missing) |
| 72 | + assert set(requested) == set(range(10, 110)) |
| 73 | + missing -= set(requested) |
| 74 | + |
| 75 | + # Cycle 2: remaining 100 recovered |
| 76 | + requested = simulate_request_slice(missing) |
| 77 | + assert set(requested) == set(range(110, 210)) |
| 78 | + missing -= set(requested) |
| 79 | + assert len(missing) == 0 |
| 80 | + |
| 81 | + def test_sustained_loss_old_gaps_still_recovered(self): |
| 82 | + """ |
| 83 | + Under sustained loss (>100 new gaps per cycle), oldest-first |
| 84 | + ensures old gaps are recovered before they age out of the |
| 85 | + car's ring buffer. |
| 86 | + """ |
| 87 | + missing = set(range(100, 150)) # 50 old gaps |
| 88 | + next_seq = 200 |
| 89 | + |
| 90 | + for cycle in range(3): |
| 91 | + for s in range(next_seq, next_seq + 120): |
| 92 | + missing.add(s) |
| 93 | + next_seq += 140 |
| 94 | + |
| 95 | + requested = simulate_request_slice(missing) |
| 96 | + missing -= set(requested) |
| 97 | + |
| 98 | + old_remaining = missing & set(range(100, 150)) |
| 99 | + assert len(old_remaining) == 0, ( |
| 100 | + "Oldest-first should recover old gaps even under sustained loss" |
| 101 | + ) |
| 102 | + |
| 103 | + def test_sustained_loss_newest_delayed_not_lost(self): |
| 104 | + """ |
| 105 | + Under sustained loss, newest gaps are delayed (not requested |
| 106 | + immediately) but eventually get their turn as older ones clear. |
| 107 | + """ |
| 108 | + missing = set(range(100, 150)) # 50 old |
| 109 | + next_seq = 200 |
| 110 | + all_ever_missing: set[int] = set(missing) |
| 111 | + |
| 112 | + for cycle in range(10): |
| 113 | + new_gaps = set(range(next_seq, next_seq + 120)) |
| 114 | + missing |= new_gaps |
| 115 | + all_ever_missing |= new_gaps |
| 116 | + next_seq += 140 |
| 117 | + |
| 118 | + requested = simulate_request_slice(missing) |
| 119 | + missing -= set(requested) |
| 120 | + |
| 121 | + # The set grows but oldest are always drained first. |
| 122 | + # With 120 new per cycle and 100 recovered, net growth is 20/cycle. |
| 123 | + # After 10 cycles: 200 remaining (all from recent cycles). |
| 124 | + # None of the old (100-149) should remain. |
| 125 | + old_remaining = missing & set(range(100, 150)) |
| 126 | + assert len(old_remaining) == 0 |
| 127 | + |
| 128 | + def test_1000_cap_evicts_oldest(self): |
| 129 | + """ |
| 130 | + The missing set cap at 1000 still evicts the oldest seqs. |
| 131 | + This is a separate mechanism from the request slice. |
| 132 | + """ |
| 133 | + stream = [0, 1501] |
| 134 | + missing, _ = simulate_gap_detection(stream) |
| 135 | + |
| 136 | + assert len(missing) <= 1000 |
| 137 | + assert min(missing) == 501 |
| 138 | + |
| 139 | + |
| 140 | +class TestRecoveryRemovesFromMissing: |
| 141 | + """Verify that successful recovery correctly shrinks the missing set.""" |
| 142 | + |
| 143 | + def test_recovery_removes_seq(self): |
| 144 | + missing = set(range(10, 20)) |
| 145 | + missing.remove(15) |
| 146 | + assert 15 not in missing |
| 147 | + assert len(missing) == 9 |
| 148 | + |
| 149 | + def test_full_recovery_empties_set(self): |
| 150 | + missing = set(range(10, 20)) |
| 151 | + for seq in range(10, 20): |
| 152 | + missing.discard(seq) |
| 153 | + assert len(missing) == 0 |
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