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ScopeDescendants asserts the shape, not an exact emission count (#946) #955

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Merged
rbuergi merged 1 commit into from
Aug 8, 2026
Merged

ScopeDescendants asserts the shape, not an exact emission count (#946) #955

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33 changes: 23 additions & 10 deletions test/MeshWeaver.Query.Test/ObservableQueryIntegrationTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -134,19 +134,32 @@ public async Task ScopeDescendants_NotifiesOnAllDescendantChanges()
await NodeFactory.CreateNode(MeshNode.FromPath($"{p}/Project/Task") with { Name = "Task", NodeType = "Code" }).Should().Emit();
await NodeFactory.CreateNode(MeshNode.FromPath($"{p}/Project/Task/Subtask") with { Name = "Subtask", NodeType = "Code" }).Should().Emit();

var changes = await accumulated.Should(WaitTimeout).Match(acc => acc.Skip(initialCount)
// 🚨 Assert the SHAPE (the three paths we created each produced an Added), never a COUNT.
// `scope:descendants` legitimately matches anything created under {p} — a satellite the
// framework writes for the new nodes lands in the same window under load — so an
// exactly-3 assertion fails whenever one extra descendant shows up, which is what made
// this the top flake of 2026-08-08 (four unrelated PRs: #927, #940, #942, #947). Counting
// emissions on a change feed that races the initial snapshot is called out in AGENTS.md
// precisely because of this failure mode.
var expected = new[] { $"{p}/Project", $"{p}/Project/Task", $"{p}/Project/Task/Subtask" };
var changes = await accumulated.Should(WaitTimeout).Match(acc =>
{
var added = acc.Skip(initialCount)
.Where(c => c.ChangeType == QueryChangeType.Added)
.SelectMany(c => c.Items)
.Select(n => n.Path)
.ToHashSet();
return expected.All(added.Contains);
});

var addedPaths = changes.Skip(initialCount)
.Where(c => c.ChangeType == QueryChangeType.Added)
.SelectMany(c => c.Items)
.Select(n => n.Path)
.Distinct()
.Count() >= 3);

var addedItems = changes.Skip(initialCount)
.Where(c => c.ChangeType == QueryChangeType.Added)
.SelectMany(c => c.Items)
.DistinctBy(n => n.Path)
.ToList();
addedItems.Should().HaveCount(3, "Each created descendant should emit an Added change");
.ToHashSet();
addedPaths.Should().Contain(expected,
"each created descendant must emit an Added change — extra descendants are allowed, "
+ "the scope matches everything under the root");
}

[Fact]
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