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test(historian): paged-vs-unpaged raw-cap fuzz, MaxReturnDataValues advertisement, cap floor of 3

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- NodeManagerHistoryReadRawCapFuzzTests: 10k seeds (env OTOPCUA_PAGING_FUZZ_ITERATIONS)
  through a real SDK node manager against wire-faithful fakes of SqlServer / QuestDB /
  Gateway that enforce the backend half of the cap; random series with ties, random
  windows (empty, on/past a tie, between samples, forward/reverse/end-only, bounds),
  N in {0,1,2,small,huge}, cap in {off,3..1000}, tie budget {3,8,65536}. Pages must
  concatenate to the cap-off one-shot answer (checked against the series), terminate
  within values + 2 (+ one empty step per oversized boundary cluster), never exceed
  the cap, never ask the backend for 0 / over-cap; refusals only past the budget.
- HistoryPaging.AdvertiseMaxReturnDataValues writes HistoryServerCapabilities/
  MaxReturnDataValues (i=11273), read back through the SDK master node manager.
- MinMaxRawValuesPerRead raised to 3: at 2 a resumed page has no room (value + its
  boundary tie + lookahead) and every value cost an empty page + CP (seed 15).
- RawPageLimit rows pin the default-cap arithmetic (9 999 first page, 9 998 resumed).

Fuzz findings recorded as follow-ups: a bounded read whose data fits one page
returns cap + 1 (end bound fitted against N, not the cap; node manager, F2);
the Gateway walk-back's cost on a sparse series under a tiny tie budget is
pre-existing (seed 320: 82 reads uncapped, 93 capped).

Refs #736

Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
This commit is contained in:
Joseph Doherty
2026-10-22 10:15:21 -04:00
parent 6669fae7e5
commit 7e8941fbdc
7 changed files with 576 additions and 23 deletions
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tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerHistoryReadRawCapFuzzTests.cs
+436
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@@ -0,0 +1,436 @@
using Opc.Ua;
using Opc.Ua.Server;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
using HistorianRead = ZB.MOM.WW.OtOpcUa.Core.Abstractions.HistoryReadResult;
using SdkHistoryReadResult = Opc.Ua.HistoryReadResult;
namespace ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests;
/// <summary>
/// R08:1.1 (#736): the paged-vs-unpaged fuzz for the server raw cap. Every paging change in this repo has had boundary
/// bugs that the hand-written cases missed (silent truncation, an endless cursor, an empty page between every value), so
/// the cap is proved the only way that has worked: random series (bursts, gaps, sub-millisecond stamps, tie clusters),
/// random windows (empty, on a tie, one step past a tie, between samples, forward / reverse / end-only, with and without
/// bounds) and random caps — <c>NumValuesPerNode</c> 0 / 1 / 2 / small / huge, the server cap 2 … 1000 or off, the
/// tie-cluster budget 3 / 8 / 65536 — paged through a REAL SDK node manager against a wire-faithful fake of each backend
/// (SqlServer: tick precision, native reverse, <c>TOP</c>; QuestDB: µs truncation of bounds AND stamps, native reverse,
/// <c>LIMIT</c>; Gateway: forward only, <c>[start, end)</c> after its own boundary-row filtering, walked back by the
/// server) that enforces the backend half of the cap exactly as the real sources do (a read asking for 0 or more than
/// the cap reads cap + 1 rows and is refused when the window holds more).
/// <para>
/// The oracle is the same node manager's one-shot answer with the cap OFF (<c>NumValuesPerNode = 0</c>, no limit),
/// which for a plain read is also checked against the series itself. The concatenation of the pages must equal it
/// exactly; the read must terminate within the number of values plus two pages; no page may exceed the cap; the fake
/// must never see a request for 0 or more than the cap (the "bounded by the same cap" invariant); and a
/// <c>BadTooManyOperations</c> is accepted only when a tie cluster (or, on the Gateway shape, one millisecond) is
/// larger than the budget that the cap and <c>MaxTieClusterOverfetch</c> leave — after an exact prefix. The run is
/// non-vacuous by construction: it asserts that empty windows, mid-tie windows, reverse reads, caps of 1 and 2 and
/// every shape occurred, and that most iterations were exact.
/// </para>
/// <para>
/// Iterations: <c>OTOPCUA_PAGING_FUZZ_ITERATIONS</c> (default 10 000, the lane gate). Seeds are stable, so a failure
/// names a reproducible seed.
/// </para>
/// </summary>
public sealed class NodeManagerHistoryReadRawCapFuzzTests(BoundsServerFixture fx) : IClassFixture<BoundsServerFixture>
{
private static readonly DateTime T0 = new(2026, 10, 22, 12, 0, 0, DateTimeKind.Utc);
/// <summary>The backend the fake is shaped like.</summary>
public enum Shape { SqlServer, QuestDb, Gateway }
private enum Direction { Forward, Reverse, EndOnly }
private static int Iterations =>
int.TryParse(Environment.GetEnvironmentVariable("OTOPCUA_PAGING_FUZZ_ITERATIONS"), out var n) && n > 0 ? n : 10_000;
[Fact]
public async Task Paged_equals_unpaged_on_random_series_windows_and_caps_and_always_terminates()
{
var iterations = Iterations;
var counts = new Dictionary<string, int>();
void Count(string key) => counts[key] = counts.GetValueOrDefault(key) + 1;
await fx.Gate.WaitAsync(TestContext.Current.CancellationToken);
try
{
for (var seed = 0; seed < iterations; seed++)
{
var rng = new Random(seed);
var shape = (Shape)(seed % 3);
var resolution = shape == Shape.QuestDb ? 10L : 1L;
var series = RandomSeries(rng, resolution);
var cap = rng.Next(10) switch { 0 => 0, 1 or 2 => 3, 3 => 4, 4 => 5, 5 => 7, 6 => 10, 7 => 16, 8 => 33, _ => 1000 };
var n = rng.Next(9) switch { 0 or 1 => 0u, 2 or 3 => 1u, 4 or 5 => 2u, 6 => (uint)rng.Next(3, 20), 7 => (uint)rng.Next(20, 200), _ => 100_000u };
var tieBudget = rng.Next(4) switch { 0 => 3, 1 => 8, _ => 65536 };
var direction = rng.Next(5) switch { 0 => Direction.Reverse, 1 => Direction.EndOnly, _ => Direction.Forward };
if (direction == Direction.EndOnly && n == 0) direction = Direction.Forward; // Part 11: one bound only with a cap
var bounds = direction != Direction.EndOnly && rng.Next(4) == 0;
var a = PickBoundary(rng, series, resolution);
var b = PickBoundary(rng, series, resolution);
var (lo, hi) = a <= b ? (a, b) : (b, a);
var (start, end) = direction switch
{
Direction.Forward => (lo, hi),
Direction.Reverse => (hi, lo),
_ => (DateTime.MinValue, hi),
};
var tag = $"seed {seed} {shape} cap {cap} N {n} tie {tieBudget} {direction} bounds {bounds} [{start:O} .. {end:O}]";
// The walk-back (Gateway shape only: reverse / end-only reads, and the bound lookups of any bounded read) refuses
// a millisecond holding more samples than its budget — computed up front, over the whole series, because the
// walk and the lookups read around the window.
var walks = shape == Shape.Gateway && (direction != Direction.Forward || bounds);
var msMax = walks ? MillisecondMax(series) : 0;
// The oracle: the one-shot answer with the cap off (and, for a plain read, the series itself).
var truthSource = new CappedFake(series, shape, cap: 0);
fx.Nm.HistoricalSourceForTest(truthSource, tieBudget);
// An end-only read is paged backward from EndTime (the node manager flips it to a reverse read down to the
// beginning of time); its oracle is the explicit reverse read down to the Unix epoch — the walk-back's floor,
// and Part 11 (the SDK checks it) needs both bounds set when NumValuesPerNode = 0.
var (truth, truthError, truthCp) = direction == Direction.EndOnly
? Read(hi, DateTime.UnixEpoch, 0, bounds: false, cp: null)
: Read(start, end, 0, bounds, cp: null);
if (truthError.StatusCode.Code == StatusCodes.BadTooManyOperations)
{
// Only the walk-back can refuse an uncapped one-shot read, and only past its budget (max(1, M) with no cap).
(walks && msMax > Math.Max(1, tieBudget)).ShouldBeTrue($"the oracle read was refused: {tag} (ms max {msMax})");
Count("oracle refused");
continue;
}
truthError.StatusCode.Code.ShouldBe(StatusCodes.Good, $"oracle: {tag}");
truthCp.ShouldBeNull($"oracle (no cap, N = 0) is one page: {tag}");
if (!bounds)
Render(truth).ShouldBe(Render(Oracle(series, start, end, direction, resolution)), $"oracle vs series: {tag}");
truthSource.OverCapRequests.ShouldBe(0, $"the uncapped oracle source must never be asked for more than it allows: {tag}");
var windowTies = LargestTieCluster(truth);
if (truth.Count == 0) Count("empty");
if (windowTies >= 2) Count("ties in window");
if (EndsOnTie(series, start, end, direction, resolution)) Count("window ends on a tie");
if (direction == Direction.Reverse) Count("reverse");
if (direction == Direction.EndOnly) Count("end-only");
if (n == 1) Count("N=1");
if (n == 2) Count("N=2");
if (n == 0) Count("N=0");
if (cap == 3) Count("cap=3");
if (bounds) Count("bounds");
Count(shape.ToString());
// A boundary tie cluster as large as the cap leaves a resumed page no room: the server steps past it with one
// empty page carrying a continuation point (the documented #694 ceiling behaviour) — the one empty page allowed.
var oversizedClusters = cap > 0
? truth.Where(v => !(v.Value is null && v.StatusCode.Code == StatusCodes.BadBoundNotFound))
.GroupBy(v => v.SourceTimestamp.Ticks).Count(g => g.Count() >= Math.Max(2, cap - 1))
: 0;
// The read under test.
var source = new CappedFake(series, shape, cap);
fx.Nm.HistoricalSourceForTest(source, tieBudget);
var pages = new List<IReadOnlyList<DataValue>>();
var collected = new List<DataValue>();
byte[]? cp = null;
StatusCode status;
do
{
var (values, error, next) = Read(start, end, n, bounds, cp);
status = error.StatusCode;
if (!StatusCode.IsGood(status)) break;
pages.Add(values);
collected.AddRange(values);
cp = next;
pages.Count.ShouldBeLessThanOrEqualTo(truth.Count + 2 + oversizedClusters, $"paging must terminate: {tag} pages {Sizes(pages)}");
}
while (cp is not null);
source.OverCapRequests.ShouldBe(0, $"the server asked the backend for 0 or more than the cap: {tag}");
source.BadRequests.ShouldBe(0, $"a reverse window reached a forward-only backend: {tag}");
if (status.Code == StatusCodes.BadTooManyOperations)
{
// Legitimate only past the budget the cap leaves: a tie cluster larger than min(M, cap − 1), or on the
// Gateway shape a millisecond holding more than min(M, cap − 2) samples (the walk-back's budget).
var overfetchBound = cap > 0 ? Math.Min(Math.Max(1, tieBudget), Math.Max(1, cap - 1)) : Math.Max(1, tieBudget);
var walkBudget = cap > 0 ? Math.Max(1, Math.Min(tieBudget, cap - 2)) : Math.Max(1, tieBudget);
var legit = windowTies > overfetchBound || (walks && msMax > walkBudget);
legit.ShouldBeTrue($"refused with no tie cluster over {overfetchBound} (max {windowTies}; ms max {msMax} vs {walkBudget}): {tag}");
Render(collected).ShouldBe(Render(truth.Take(collected.Count)), $"the prefix before the refusal: {tag}");
Count("refused");
continue;
}
status.Code.ShouldBe(StatusCodes.Good, $"{tag}");
Render(collected).ShouldBe(Render(truth), $"paged ≠ unpaged: {tag} pages {Sizes(pages)}");
if (cap > 0)
{
// A bounded read whose data fits one page carries its start bound, the data and its end bound: the node
// manager fits the end bound against the client's N but not against the server cap (follow-up F2), so that
// one page may hold cap + 1 values; every other page is at most the cap.
var bothBoundsOnOnePage = bounds && pages.Count == 1;
pages.ShouldAllBe(p => p.Count <= cap + (bothBoundsOnOnePage ? 1 : 0), $"a page over the cap: {tag} pages {Sizes(pages)}");
if (bothBoundsOnOnePage && pages[0].Count == cap + 1) Count("bounded single page at cap+1 (F2)");
}
if (n > 0) pages.ShouldAllBe(p => p.Count <= n, $"a page over N: {tag} pages {Sizes(pages)}");
for (var i = 0; i < pages.Count - 1; i++)
{
if (pages[i].Count > 0) continue;
// Allowed only as the step past a boundary tie cluster the cap cannot page within.
var previousLast = i > 0 && pages[i - 1].Count > 0 ? pages[i - 1][^1].SourceTimestamp.Ticks : (long?)null;
var clusterAtBoundary = previousLast is { } t ? truth.Count(v => v.SourceTimestamp.Ticks == t) : 0;
(cap > 0 && clusterAtBoundary >= Math.Max(2, cap - 1)).ShouldBeTrue(
$"an empty page with a continuation point (page {i}, boundary cluster {clusterAtBoundary}): {tag} pages {Sizes(pages)}");
Count("empty step over an oversized tie cluster");
}
if (pages.Count > 1) Count("paged");
if (pages.Count > 1 && n == 0) Count("paged at N=0");
// A cost guard against a read explosion, not a budget. A native shape reads once per page plus the bound
// lookups. The Gateway shape's walk-back has its own cost profile — ~30 reads a page on a dense tag
// (#691/#693), far more on a sparse series under a tiny tie budget (seed 320: 82 reads with NO cap, seed 6428:
// 120+) — so it is judged RELATIVE to the same request with the cap off (the pre-#736 behaviour), per page:
// the cap must not make the walk explode compared to before. The baseline asks for the page size the cap
// imposes (N = cap − 1): an uncapped N = 0 reverse read used to be ONE int.MaxValue forward read — the very
// memory vector the cap removes — so "what N = 0 cost before" is not the comparison.
var allowedReads = 8 * pages.Count + 8;
if (shape == Shape.Gateway)
{
var baseline = new CappedFake(series, shape, cap: 0);
fx.Nm.HistoricalSourceForTest(baseline, tieBudget);
var baseN = cap > 0 && (n == 0 || n > (uint)cap) ? (uint)(cap - 1) : n;
var basePages = 0;
byte[]? baseCp = null;
do
{
var (_, baseError, next) = Read(start, end, baseN, bounds, baseCp);
if (!StatusCode.IsGood(baseError.StatusCode)) break;
basePages++;
baseCp = next;
}
while (baseCp is not null && basePages <= truth.Count + 2 + oversizedClusters);
allowedReads = 2 * baseline.Reads * Math.Max(1, pages.Count) / Math.Max(1, basePages) + 32 * pages.Count + 16;
}
source.Reads.ShouldBeLessThanOrEqualTo(allowedReads,
$"backend reads exploded: {source.Reads} for {pages.Count} pages (allowed {allowedReads}): {tag}");
Count("exact");
}
}
finally
{
fx.Nm.HistoricalSourceForTest(NullHistorianDataSource.Instance, 65536);
fx.Gate.Release();
}
// Non-vacuous: every category the brief names occurred, and most runs were exact.
var summary = string.Join(", ", counts.OrderBy(kv => kv.Key).Select(kv => $"{kv.Key}={kv.Value}"));
foreach (var required in new[] { "empty", "ties in window", "window ends on a tie", "reverse", "end-only", "N=1", "N=2", "N=0", "cap=3", "bounds", "paged", "paged at N=0", "SqlServer", "QuestDb", "Gateway" })
counts.GetValueOrDefault(required).ShouldBeGreaterThan(iterations / 200, $"{required} under-represented: {summary}");
counts.GetValueOrDefault("exact").ShouldBeGreaterThan(iterations * 6 / 10, summary);
TestContext.Current.TestOutputHelper?.WriteLine($"raw-cap fuzz: {iterations} iterations — {summary}");
}
// --- generators -----------------------------------------------------------------------------
private static DateTime Ts(DataValueSnapshot s) => s.SourceTimestampUtc ?? DateTime.MinValue;
private static DateTime Trunc(DateTime t, long resolution) => new(t.Ticks - t.Ticks % resolution, DateTimeKind.Utc);
/// <summary>Random ascending series: bursts, gaps, sub-millisecond stamps and tie clusters; stamps stored at the resolution.</summary>
private static List<DataValueSnapshot> RandomSeries(Random rng, long resolution)
{
var list = new List<DataValueSnapshot>();
var t = T0.Ticks - rng.Next(0, 3) * TimeSpan.TicksPerHour;
var count = rng.Next(1, 120);
var v = 0;
while (list.Count < count)
{
t += rng.Next(6) switch
{
0 => rng.Next(1, 10), // sub-millisecond (sub-µs on QuestDB: collapses onto a tie)
1 => rng.Next(1, 5) * TimeSpan.TicksPerMillisecond, // dense
2 => rng.Next(1, 3) * TimeSpan.TicksPerSecond,
3 => rng.Next(1, 30) * TimeSpan.TicksPerMinute, // a gap
_ => rng.Next(1, 1000) * TimeSpan.TicksPerMillisecond,
};
var ties = rng.Next(7) == 0 ? rng.Next(2, 9) : 1;
for (var k = 0; k < ties; k++)
{
var ts = Trunc(new DateTime(t, DateTimeKind.Utc), resolution);
var status = rng.Next(12) == 0 ? StatusCodes.Bad : StatusCodes.Good;
list.Add(new DataValueSnapshot(status == StatusCodes.Bad ? null : (double)v, status, ts, ts));
v++;
}
}
return list;
}
/// <summary>A window bound: before / after the data, exactly on a sample (a tie, maybe), one step past one, a tick before one, or between two.</summary>
private static DateTime PickBoundary(Random rng, List<DataValueSnapshot> series, long resolution)
{
var first = Ts(series[0]);
var last = Ts(series[^1]);
var i = rng.Next(series.Count);
var t = Ts(series[i]);
switch (rng.Next(9))
{
case 0: return first.AddSeconds(-rng.Next(1, 100));
case 1: return last.AddSeconds(rng.Next(1, 100));
case 2:
case 3: return t;
case 4: return t.AddTicks(resolution);
case 5: return t.AddTicks(-1); // sub-resolution: a microsecond backend truncates it back ONTO the sample
case 6: return t.AddMilliseconds(1);
default:
var next = i + 1 < series.Count ? Ts(series[i + 1]) : t.AddSeconds(10);
return new DateTime(t.Ticks + (long)((next.Ticks - t.Ticks) * rng.NextDouble()), DateTimeKind.Utc);
}
}
/// <summary>The series' own answer for a plain (no bounds) read: forward <c>[start, end)</c>, point, reverse / end-only <c>(end, start]</c> newest first.</summary>
private static List<DataValue> Oracle(List<DataValueSnapshot> series, DateTime start, DateTime end, Direction direction, long resolution)
{
var s = Trunc(start, resolution);
var e = Trunc(end, resolution);
IEnumerable<DataValueSnapshot> window = direction switch
{
// start == end is Part 11's point read whichever way it was generated: the node manager reads it forward.
Direction.Forward or Direction.Reverse when s == e => series.Where(x => Ts(x) == s),
Direction.Forward => series.Where(x => Ts(x) >= s && Ts(x) < e),
Direction.Reverse => series.Where(x => Ts(x) > e && Ts(x) <= s).Reverse(),
_ => series.Where(x => Ts(x) <= e).Reverse(),
};
return window.Select(x => new DataValue(new Variant(x.Value), new StatusCode(x.StatusCode), Ts(x), Ts(x))).ToList();
}
/// <summary>The largest tie cluster among the returned stored values (a bound placeholder is not a stored value).</summary>
private static int LargestTieCluster(IReadOnlyList<DataValue> truth) =>
truth.Where(v => !(v.Value is null && v.StatusCode.Code == StatusCodes.BadBoundNotFound))
.GroupBy(v => v.SourceTimestamp.Ticks).Select(g => g.Count()).DefaultIfEmpty(0).Max();
/// <summary>The most samples within one millisecond anywhere in the series (the walk-back's refusal rule).</summary>
private static int MillisecondMax(List<DataValueSnapshot> series)
{
var msMax = 0;
for (int i = 0, j = 0; i < series.Count; i++)
{
while (Ts(series[i]).Ticks - Ts(series[j]).Ticks >= TimeSpan.TicksPerMillisecond) j++;
msMax = Math.Max(msMax, i - j + 1);
}
return msMax;
}
private static bool EndsOnTie(List<DataValueSnapshot> series, DateTime start, DateTime end, Direction direction, long resolution)
{
var edge = Trunc(direction == Direction.Forward ? end : direction == Direction.Reverse ? start : end, resolution);
return series.Count(x => Ts(x) == edge) >= 2;
}
// --- helpers ----------------------------------------------------------------------------------
private static string Sizes(IEnumerable<IReadOnlyList<DataValue>> pages) => "[" + string.Join(",", pages.Select(p => p.Count)) + "]";
private static string Render(IEnumerable<DataValue> values) =>
string.Join(" | ", values.Select(v => $"{v.SourceTimestamp.Ticks}={v.Value ?? "null"}/{v.StatusCode.Code:X8}"));
private (IReadOnlyList<DataValue> Values, ServiceResult Error, byte[]? Cp) Read(DateTime start, DateTime end, uint max, bool bounds, byte[]? cp)
{
var context = new OperationContext(new RequestHeader(), secureChannelContext: null, RequestType.HistoryRead, identity: null);
var details = new ReadRawModifiedDetails
{
StartTime = start, EndTime = end, NumValuesPerNode = max, ReturnBounds = bounds, IsReadModified = false,
};
var nodesToRead = new List<HistoryReadValueId> { new() { NodeId = fx.NodeId, ContinuationPoint = cp } };
var results = new List<SdkHistoryReadResult> { null! };
var errors = new List<ServiceResult> { null! };
fx.Nm.HistoryRead(context, details, TimestampsToReturn.Both, releaseContinuationPoints: false, nodesToRead, results, errors);
var values = new List<DataValue>();
if (results[0]?.HistoryData is { } ho && !ExtensionObject.IsNull(ho))
values.AddRange(((HistoryData)ExtensionObject.ToEncodeable(ho)).DataValues);
return (values, errors[0], results[0]?.ContinuationPoint);
}
/// <summary>
/// A series-backed historian shaped like one backend, enforcing the backend half of the server raw cap exactly as
/// the real data sources do: it reports the cap as <see cref="MaxRawValuesPerRead"/>; a read asking for 0 or more than
/// the cap reads cap + 1 rows and throws <see cref="HistoryReadLimitExceededException"/> when the window holds more
/// (never a truncated answer). It also records every such request (<see cref="OverCapRequests"/>) — the server must
/// never issue one — and every reverse window sent to the forward-only shape (<see cref="BadRequests"/>).
/// </summary>
private sealed class CappedFake(IReadOnlyList<DataValueSnapshot> series, Shape shape, int cap) : IHistorianDataSource
{
private readonly Lock _gate = new();
public int Reads { get; private set; }
public int OverCapRequests { get; private set; }
public int BadRequests { get; private set; }
public bool SupportsReverseRaw => shape != Shape.Gateway;
public long TimestampResolutionTicks => shape == Shape.QuestDb ? 10 : 1;
public int MaxRawValuesPerRead => cap;
private DateTime Trunc(DateTime t) => NodeManagerHistoryReadRawCapFuzzTests.Trunc(t, TimestampResolutionTicks);
public Task<HistorianRead> ReadRawAsync(
string fullReference, DateTime startUtc, DateTime endUtc, uint maxValuesPerNode, CancellationToken cancellationToken)
{
var probe = cap > 0 && (maxValuesPerNode == 0 || maxValuesPerNode > (uint)cap);
lock (_gate)
{
Reads++;
if (probe) OverCapRequests++;
if (shape == Shape.Gateway && startUtc > endUtc) BadRequests++;
}
if (shape == Shape.Gateway && startUtc > endUtc)
throw new InvalidOperationException("start_time must be less than or equal to end_time. (InvalidArgument)");
startUtc = Trunc(startUtc);
endUtc = Trunc(endUtc);
List<DataValueSnapshot> window;
if (startUtc > endUtc) window = series.Where(s => Ts(s) > endUtc && Ts(s) <= startUtc).Reverse().ToList();
else if (startUtc == endUtc) window = series.Where(s => Ts(s) == startUtc).ToList();
else window = series.Where(s => Ts(s) >= startUtc && Ts(s) < endUtc).ToList();
var top = probe ? cap + 1 : maxValuesPerNode == 0 ? int.MaxValue : (int)Math.Min(maxValuesPerNode, int.MaxValue);
var page = window.Take(top).ToList();
if (probe && page.Count > cap)
throw new HistoryReadLimitExceededException(cap, $"more than MaxRawValuesPerRead ({cap}) samples");
return Task.FromResult(new HistorianRead(page, null));
}
public Task<HistorianRead> ReadProcessedAsync(
string fullReference, DateTime startUtc, DateTime endUtc, TimeSpan interval,
HistoryAggregateType aggregate, CancellationToken cancellationToken) =>
Task.FromResult(new HistorianRead(Array.Empty<DataValueSnapshot>(), null));
public Task<HistorianRead> ReadAtTimeAsync(
string fullReference, IReadOnlyList<DateTime> timestampsUtc, CancellationToken cancellationToken) =>
Task.FromResult(new HistorianRead(Array.Empty<DataValueSnapshot>(), null));
public Task<HistoricalEventsResult> ReadEventsAsync(
string? sourceName, DateTime startUtc, DateTime endUtc, int maxEvents, CancellationToken cancellationToken) =>
Task.FromResult(new HistoricalEventsResult(Array.Empty<HistoricalEvent>(), null));
public HistorianHealthSnapshot GetHealthSnapshot() => NullHistorianDataSource.Instance.GetHealthSnapshot();
public void Dispose() { }
}
}
/// <summary>Test-only wiring shared by the paging fuzz: swap the source and the tie budget, with a fresh continuation store.</summary>
internal static class NodeManagerFuzzExtensions
{
public static void HistoricalSourceForTest(this OtOpcUaNodeManager nm, IHistorianDataSource source, int tieBudget)
{
nm.HistoryContinuationStore = new InMemoryHistoryContinuationStore();
nm.MaxTieClusterOverfetch = tieBudget;
nm.HistorianDataSource = source;
}
}