Joseph Doherty
82372f1672
STAB-21 ConnectionBackoff in EnsureConnectedAsync; STAB-22 write-pass accumulator with a write-side Faulted that a clean read does not erase; _health on the Volatile idiom; S7-016 contiguous array write (Bool arrays stay refused). Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
383 lines
18 KiB
C#
383 lines
18 KiB
C#
using Microsoft.Extensions.Logging;
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using S7.Net;
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using Shouldly;
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using Xunit;
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using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
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using ZB.MOM.WW.OtOpcUa.Core.Hosting;
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using S7NetDataType = global::S7.Net.DataType;
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using S7DataItem = global::S7.Net.Types.DataItem;
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namespace ZB.MOM.WW.OtOpcUa.Driver.S7.Tests;
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/// <summary>
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/// #602 / #610 S7 items: array write path (S7-016), connect backoff (STAB-21), the write-pass
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/// worst-state-wins accumulator (STAB-22) and the factory logger (CONV-3). All against an
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/// in-memory <see cref="IS7Plc"/> — no live PLC, no fixture.
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/// </summary>
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[Trait("Category", "Unit")]
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public sealed class S7ArrayWriteAndHealthTests
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{
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private const uint BadTypeMismatch = 0x80740000u;
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private const uint BadNotSupported = 0x803D0000u;
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private static S7TagDefinition Arr(S7DataType dt, string addr, int count, bool writable = true) =>
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new("Arr", addr, dt, Writable: writable, ArrayCount: count);
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private static S7DriverOptions Options(params S7TagDefinition[] tags) => new()
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{
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Host = "192.0.2.1",
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Timeout = TimeSpan.FromMilliseconds(250),
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Probe = new S7ProbeOptions { Enabled = false },
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RawTags = S7RawTags.Entries(tags),
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};
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// ---- pure codec ----
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/// <summary>Encode is the exact inverse of <see cref="S7Driver.DecodeArrayBlock"/> for every supported element type.</summary>
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[Theory]
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[InlineData(S7DataType.Byte, "DB1.DBB0")]
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[InlineData(S7DataType.Int16, "DB1.DBW0")]
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[InlineData(S7DataType.UInt16, "DB1.DBW0")]
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[InlineData(S7DataType.Int32, "DB1.DBD0")]
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[InlineData(S7DataType.UInt32, "DB1.DBD0")]
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[InlineData(S7DataType.Float32, "DB1.DBD0")]
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public void EncodeArrayBlock_round_trips_through_DecodeArrayBlock(S7DataType dt, string addrText)
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{
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var tag = Arr(dt, addrText, 3);
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var addr = S7AddressParser.Parse(addrText);
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object source = dt switch
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{
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S7DataType.Byte => new byte[] { 1, 200, 255 },
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S7DataType.Int16 => new short[] { -1, 0, 32000 },
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S7DataType.UInt16 => new ushort[] { 1, 0, 65535 },
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S7DataType.Int32 => new[] { -5, 0, int.MaxValue },
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S7DataType.UInt32 => new uint[] { 1, 0, uint.MaxValue },
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_ => new[] { -1.5f, 0f, 3.25f },
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};
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var block = S7Driver.EncodeArrayBlock(tag, addr, source);
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block.Length.ShouldBe(3 * S7Driver.ElementByteSize(addr.Size));
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S7Driver.DecodeArrayBlock(tag, addr, block).ShouldBe(source);
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}
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/// <summary>Big-endian layout is pinned byte-for-byte for Int16.</summary>
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[Fact]
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public void EncodeArrayBlock_is_big_endian()
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{
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var tag = Arr(S7DataType.Int16, "DB1.DBW0", 2);
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S7Driver.EncodeArrayBlock(tag, S7AddressParser.Parse("DB1.DBW0"), new short[] { 0x0102, -2 })
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.ShouldBe(new byte[] { 0x01, 0x02, 0xFF, 0xFE });
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}
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/// <summary>A non-array, a string, a wrong length and an unconvertible element are client errors, not comms faults.</summary>
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[Fact]
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public void EncodeArrayBlock_rejects_wrongly_shaped_values()
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{
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var tag = Arr(S7DataType.Int16, "DB1.DBW0", 2);
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var addr = S7AddressParser.Parse("DB1.DBW0");
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Should.Throw<S7Driver.S7WriteValueException>(() => S7Driver.EncodeArrayBlock(tag, addr, (short)1));
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Should.Throw<S7Driver.S7WriteValueException>(() => S7Driver.EncodeArrayBlock(tag, addr, "ab"));
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Should.Throw<S7Driver.S7WriteValueException>(() => S7Driver.EncodeArrayBlock(tag, addr, new short[] { 1 }));
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Should.Throw<S7Driver.S7WriteValueException>(() => S7Driver.EncodeArrayBlock(tag, addr, new[] { 1, 2, 3 }));
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Should.Throw<S7Driver.S7WriteValueException>(() => S7Driver.EncodeArrayBlock(tag, addr, new object[] { 1, 70000 })); // overflow
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Should.Throw<S7Driver.S7WriteValueException>(() => S7Driver.EncodeArrayBlock(tag, addr, new object[] { 1, "x" })); // format
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}
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/// <summary>Bool and wide-type arrays are refused with NotSupported (BadNotSupported on the wire).</summary>
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[Theory]
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[InlineData(S7DataType.Bool, "DB1.DBX0.0")]
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[InlineData(S7DataType.Int64, "DB1.DBB0")]
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[InlineData(S7DataType.String, "DB1.DBB0")]
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public void EncodeArrayBlock_refuses_bool_and_wide_arrays(S7DataType dt, string addrText)
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{
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Should.Throw<NotSupportedException>(() => S7Driver.EncodeArrayBlock(
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Arr(dt, addrText, 2), S7AddressParser.Parse(addrText), new object[] { 1, 2 }));
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}
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// ---- WriteAsync array path ----
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/// <summary>
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/// A valid array write issues exactly ONE contiguous WriteBytes at the tag's DB/offset
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/// (S7-016) and reports Good. The bytes are the decode inverse, so a following read returns the value.
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/// </summary>
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[Fact]
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public async Task Write_array_issues_one_contiguous_block_write()
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{
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var factory = new RecordingFactory();
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using var drv = new S7Driver(Options(Arr(S7DataType.Int16, "DB5.DBW10", 3)), "s7-arr-write", factory);
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await drv.InitializeAsync("{}", TestContext.Current.CancellationToken);
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var res = await drv.WriteAsync([new WriteRequest("Arr", new short[] { 1, 2, 3 })], TestContext.Current.CancellationToken);
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res[0].StatusCode.ShouldBe(0u);
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var w = factory.Created[0].BlockWrites.ShouldHaveSingleItem();
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w.Area.ShouldBe(S7NetDataType.DataBlock);
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w.Db.ShouldBe(5);
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w.Start.ShouldBe(10);
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w.Bytes.ShouldBe(new byte[] { 0, 1, 0, 2, 0, 3 });
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factory.Created[0].ScalarWrites.ShouldBe(0);
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drv.GetHealth().State.ShouldBe(DriverState.Healthy);
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}
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/// <summary>
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/// A wrong-length array is BadTypeMismatch, writes nothing and leaves health untouched; the
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/// positive control is the valid write in the same batch landing.
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/// </summary>
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[Fact]
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public async Task Write_array_with_wrong_length_is_BadTypeMismatch_and_not_a_health_event()
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{
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var factory = new RecordingFactory();
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using var drv = new S7Driver(Options(Arr(S7DataType.Int16, "DB1.DBW0", 3)), "s7-arr-len", factory);
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await drv.InitializeAsync("{}", TestContext.Current.CancellationToken);
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var res = await drv.WriteAsync(
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[new WriteRequest("Arr", new short[] { 1, 2 }), new WriteRequest("Arr", new short[] { 7, 8, 9 })],
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TestContext.Current.CancellationToken);
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res[0].StatusCode.ShouldBe(BadTypeMismatch);
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res[1].StatusCode.ShouldBe(0u);
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factory.Created[0].BlockWrites.Count.ShouldBe(1); // only the valid one reached the wire
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drv.GetHealth().State.ShouldBe(DriverState.Healthy);
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}
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// ---- STAB-21 connect backoff ----
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/// <summary>
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/// A dead PLC costs ONE connect attempt per backoff window, not one per read; the window grows
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/// (1 s then 2 s), and a successful connect clears it so recovery is immediate.
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/// </summary>
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[Fact]
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public async Task Dead_plc_costs_one_connect_attempt_per_backoff_window()
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{
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var factory = new RecordingFactory();
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using var drv = new S7Driver(Options(new S7TagDefinition("W0", "DB1.DBW0", S7DataType.UInt16)), "s7-backoff", factory);
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var now = new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc);
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drv.BackoffClock = () => now;
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await drv.InitializeAsync("{}", TestContext.Current.CancellationToken);
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factory.Created.Count.ShouldBe(1);
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// Drop the link; every subsequent open is refused.
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factory.Created[0].NextReadThrows = new PlcException(ErrorCode.ConnectionError, "dropped");
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factory.OpenThrows = new PlcException(ErrorCode.ConnectionError, "down");
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await drv.ReadAsync(["W0"], TestContext.Current.CancellationToken); // marks dead
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// First attempt after the drop: really tries (and fails), opening a 1 s window.
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(await drv.ReadAsync(["W0"], TestContext.Current.CancellationToken))[0].StatusCode.ShouldNotBe(0u);
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factory.Created.Count.ShouldBe(2);
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// Ten more reads inside the window: no further connect attempt, still a Bad result.
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for (var i = 0; i < 10; i++)
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(await drv.ReadAsync(["W0"], TestContext.Current.CancellationToken))[0].StatusCode.ShouldNotBe(0u);
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factory.Created.Count.ShouldBe(2);
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drv.GetHealth().State.ShouldBe(DriverState.Degraded);
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// Window elapses -> exactly one more attempt (fails -> 2 s window).
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now += TimeSpan.FromSeconds(1.1);
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await drv.ReadAsync(["W0"], TestContext.Current.CancellationToken);
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factory.Created.Count.ShouldBe(3);
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now += TimeSpan.FromSeconds(1.1); // inside the doubled window
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await drv.ReadAsync(["W0"], TestContext.Current.CancellationToken);
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factory.Created.Count.ShouldBe(3);
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// PLC returns; once the window passes the next read reconnects and the window is cleared.
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factory.OpenThrows = null;
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now += TimeSpan.FromSeconds(5);
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(await drv.ReadAsync(["W0"], TestContext.Current.CancellationToken))[0].StatusCode.ShouldBe(0u);
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factory.Created.Count.ShouldBe(4);
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drv.GetHealth().State.ShouldBe(DriverState.Healthy);
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// A fresh drop reconnects immediately (no residual window).
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factory.Created[3].NextReadThrows = new PlcException(ErrorCode.ConnectionError, "dropped again");
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await drv.ReadAsync(["W0"], TestContext.Current.CancellationToken);
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(await drv.ReadAsync(["W0"], TestContext.Current.CancellationToken))[0].StatusCode.ShouldBe(0u);
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factory.Created.Count.ShouldBe(5);
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}
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// ---- STAB-22 write-pass worst-state-wins ----
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private static async Task<(S7Driver Drv, RecordingFactory Factory)> TwoTagDriver()
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{
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var factory = new RecordingFactory();
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var drv = new S7Driver(Options(
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new S7TagDefinition("A", "DB1.DBW0", S7DataType.UInt16, Writable: true),
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new S7TagDefinition("B", "DB1.DBW2", S7DataType.UInt16, Writable: true),
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new S7TagDefinition("C", "DB1.DBW4", S7DataType.UInt16, Writable: true)), "s7-writepass", factory);
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await drv.InitializeAsync("{}", TestContext.Current.CancellationToken);
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return (drv, factory);
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}
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/// <summary>
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/// Access-denied (Faulted) followed by a generic failure (Degraded) and a success in ONE batch
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/// must report Faulted with the access-denied message - not whichever item came last.
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/// </summary>
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[Fact]
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public async Task Write_batch_reports_worst_state_not_last_item()
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{
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var (drv, factory) = await TwoTagDriver();
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using var _ = drv;
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factory.Created[0].WriteFaults["DB1.DBW0"] = new PlcException(ErrorCode.WriteData, "Accessing object not allowed");
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factory.Created[0].WriteFaults["DB1.DBW2"] = new IOException("socket glitch");
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var res = await drv.WriteAsync(
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[new WriteRequest("A", (ushort)1), new WriteRequest("B", (ushort)2), new WriteRequest("C", (ushort)3)],
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TestContext.Current.CancellationToken);
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res[2].StatusCode.ShouldBe(0u);
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var h = drv.GetHealth();
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h.State.ShouldBe(DriverState.Faulted);
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h.LastError.ShouldNotBeNull().ShouldContain("PUT/GET");
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}
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/// <summary>
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/// A clean READ pass must not erase the write-side Faulted; the next write that succeeds clears
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/// it, after which a read pass reports Healthy again.
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/// </summary>
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[Fact]
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public async Task Read_pass_does_not_erase_write_fault_until_a_write_succeeds()
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{
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var (drv, factory) = await TwoTagDriver();
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using var _ = drv;
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var plc = factory.Created[0];
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plc.WriteFaults["DB1.DBW0"] = new PlcException(ErrorCode.WriteData, "Accessing object not allowed");
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await drv.WriteAsync([new WriteRequest("A", (ushort)1)], TestContext.Current.CancellationToken);
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drv.GetHealth().State.ShouldBe(DriverState.Faulted);
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// Clean read of a different tag - reads work against a write-protected CPU.
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var read = await drv.ReadAsync(["B"], TestContext.Current.CancellationToken);
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read[0].StatusCode.ShouldBe(0u);
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var h = drv.GetHealth();
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h.State.ShouldBe(DriverState.Faulted); // not erased
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h.LastSuccessfulRead.ShouldNotBeNull(); // but the read still advanced the watchdog evidence
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// A write that gets through retires the fault ...
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await drv.WriteAsync([new WriteRequest("B", (ushort)2)], TestContext.Current.CancellationToken);
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drv.GetHealth().State.ShouldBe(DriverState.Healthy);
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// ... and the next read pass stays Healthy (the sticky state is really gone).
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(await drv.ReadAsync(["B"], TestContext.Current.CancellationToken))[0].StatusCode.ShouldBe(0u);
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drv.GetHealth().State.ShouldBe(DriverState.Healthy);
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}
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/// <summary>A transient (Degraded) write failure is still erased by a clean read, as before.</summary>
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[Fact]
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public async Task Degraded_write_failure_is_still_cleared_by_a_clean_read()
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{
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var (drv, factory) = await TwoTagDriver();
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using var _ = drv;
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factory.Created[0].WriteFaults["DB1.DBW0"] = new IOException("glitch");
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await drv.WriteAsync([new WriteRequest("A", (ushort)1)], TestContext.Current.CancellationToken);
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drv.GetHealth().State.ShouldBe(DriverState.Degraded);
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(await drv.ReadAsync(["B"], TestContext.Current.CancellationToken))[0].StatusCode.ShouldBe(0u);
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drv.GetHealth().State.ShouldBe(DriverState.Healthy);
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}
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// ---- CONV-3 ----
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/// <summary>
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/// The registered factory builds drivers on the host logger: a failed connect reaches the
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/// supplied <see cref="ILoggerFactory"/>. Before CONV-3 the factory took no logger and the driver ran on the null logger.
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/// </summary>
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[Fact]
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public async Task Factory_threads_the_logger_factory_into_the_driver()
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{
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const string Json = """{"host":"192.0.2.1","timeoutMs":200}""";
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var withLogger = new CapturingLoggerFactory();
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var registry = new DriverFactoryRegistry();
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S7DriverFactoryExtensions.Register(registry, withLogger);
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var drv = registry.TryGet(S7DriverFactoryExtensions.DriverTypeName)!("s7-logs", Json);
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try { await drv.InitializeAsync(Json, TestContext.Current.CancellationToken); } catch { /* unreachable host by design */ }
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withLogger.Messages.ShouldContain(m => m.Contains("connect failed", StringComparison.OrdinalIgnoreCase));
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}
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private sealed class CapturingLoggerFactory : ILoggerFactory
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{
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public List<string> Messages { get; } = [];
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public void AddProvider(ILoggerProvider provider) { }
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public ILogger CreateLogger(string categoryName) => new Capture(this);
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public void Dispose() { }
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private sealed class Capture(CapturingLoggerFactory owner) : ILogger
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{
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public IDisposable? BeginScope<TState>(TState state) where TState : notnull => null;
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public bool IsEnabled(LogLevel logLevel) => true;
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public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception,
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Func<TState, Exception?, string> formatter)
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{
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lock (owner.Messages) owner.Messages.Add(formatter(state, exception));
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}
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}
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}
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// ---- in-memory PLC ----
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private sealed class RecordingFactory : IS7PlcFactory
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{
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public List<RecordingPlc> Created { get; } = [];
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/// <summary>When set, every connection created from now on throws this from OpenAsync.</summary>
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public Exception? OpenThrows { get; set; }
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public IS7Plc Create(S7CpuType cpuType, string host, int port, short rack, short slot, TimeSpan timeout)
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{
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var plc = new RecordingPlc { OpenThrowsAlways = OpenThrows };
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Created.Add(plc);
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return plc;
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}
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}
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private sealed class RecordingPlc : IS7Plc
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{
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public bool IsConnected { get; private set; }
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public Exception? OpenThrowsAlways { get; init; }
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public Exception? NextReadThrows { get; set; }
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public Dictionary<string, Exception> WriteFaults { get; } = new(StringComparer.Ordinal);
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public List<(S7NetDataType Area, int Db, int Start, byte[] Bytes)> BlockWrites { get; } = [];
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public int ScalarWrites { get; private set; }
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public Task OpenAsync(CancellationToken cancellationToken)
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{
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if (OpenThrowsAlways is { } ex) throw ex;
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IsConnected = true;
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return Task.CompletedTask;
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}
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public void Close() => IsConnected = false;
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public Task<object?> ReadAsync(string address, CancellationToken cancellationToken)
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{
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if (NextReadThrows is { } ex) { NextReadThrows = null; throw ex; }
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return Task.FromResult<object?>((ushort)42);
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}
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public Task<byte[]> ReadBytesAsync(S7NetDataType area, int db, int startByteAdr, int count, CancellationToken cancellationToken)
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{
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if (NextReadThrows is { } ex) { NextReadThrows = null; throw ex; }
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return Task.FromResult(new byte[count]);
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}
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public Task<IReadOnlyList<S7DataItem>> ReadMultipleVarsAsync(List<S7DataItem> items, CancellationToken cancellationToken) =>
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throw new NotSupportedException("not needed");
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public Task WriteAsync(string address, object value, CancellationToken cancellationToken)
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{
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ScalarWrites++;
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if (WriteFaults.TryGetValue(address, out var ex)) throw ex;
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return Task.CompletedTask;
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}
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public Task WriteBytesAsync(S7NetDataType area, int db, int startByteAdr, byte[] value, CancellationToken cancellationToken)
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{
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BlockWrites.Add((area, db, startByteAdr, value));
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return Task.CompletedTask;
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}
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public Task ReadStatusAsync(CancellationToken cancellationToken) => Task.CompletedTask;
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public void Dispose() => IsConnected = false;
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}
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}
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