From 7302b948a5f4a6ccbf290a140cf62985dc9af641 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Tue, 22 Sep 2026 18:06:51 +0000
Subject: [PATCH] Tests: add coverage for AsyncSeq.zipWithIndexAsync and
 AsyncSeq.ofIQueryable

Both functions previously had no dedicated test coverage. zipWithIndexAsync
is an obsolete alias for mapiAsync (retained for backward compatibility);
ofIQueryable casts an IQueryable<'T> to IAsyncEnumerable<'T> for LINQ
provider integrations such as EF Core. No functional changes.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 RELEASE_NOTES.md                              |  1 +
 .../AsyncSeqTests.fs                          | 66 +++++++++++++++++++
 2 files changed, 67 insertions(+)

diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index d96928c..d9169ed 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -1,5 +1,6 @@
 ### Unreleased
 
+* Test coverage: Added tests for `AsyncSeq.zipWithIndexAsync` (obsolete alias for `mapiAsync`) and `AsyncSeq.ofIQueryable`, which previously had no dedicated test coverage. No functional changes.
 * Test coverage: Added tests for previously-untested public API functions `AsyncSeq.tryFirst`, `AsyncSeq.firstOrDefault`, `AsyncSeq.zipWithParallel`, `AsyncSeq.combineLatestWithAsync`, and `AsyncSeq.toObservable`. No functional changes.
 * Fixed Fable CI build: `Microsoft.Bcl.AsyncInterfaces` was pinned to a specific version (`10.0.7`) that was older than the version resolved transitively via `System.Threading.Channels`, causing a `NU1605` package downgrade error that made Fable's project cracker fail during `dotnet fable`. The reference now uses `Version="*"` (matching `System.Threading.Channels`) so both resolve consistently. (#334)
 * Tests: Added comprehensive tests for `AsyncSeq.zapp`, `AsyncSeq.zappAsync`, and `AsyncSeq.compareWithAsync`, which previously had no dedicated test coverage.
diff --git a/tests/FSharp.Control.AsyncSeq.Tests/AsyncSeqTests.fs b/tests/FSharp.Control.AsyncSeq.Tests/AsyncSeqTests.fs
index 03f8dc0..167ecd5 100644
--- a/tests/FSharp.Control.AsyncSeq.Tests/AsyncSeqTests.fs
+++ b/tests/FSharp.Control.AsyncSeq.Tests/AsyncSeqTests.fs
@@ -6,6 +6,8 @@
 #endif
 module AsyncSeqTests
 
+#nowarn "44" // suppress Obsolete warnings for intentional tests of obsolete API (e.g. AsyncSeq.zipWithIndexAsync)
+
 open NUnit.Framework
 open FSharp.Control
 open System
@@ -5277,3 +5279,67 @@ let ``AsyncSeq.compareWithAsync empty sequences returns 0`` () =
       AsyncSeq.empty<int>
     |> Async.RunSynchronously
   Assert.AreEqual(0, result)
+
+// ===== zipWithIndexAsync (obsolete alias for mapiAsync) =====
+
+[<Test>]
+let ``AsyncSeq.zipWithIndexAsync maps elements with their int64 index`` () =
+  let result =
+    AsyncSeq.ofSeq ["a"; "b"; "c"]
+    |> AsyncSeq.zipWithIndexAsync (fun i x -> async { return sprintf "%d:%s" i x })
+    |> AsyncSeq.toArrayAsync
+    |> Async.RunSynchronously
+  Assert.AreEqual([| "0:a"; "1:b"; "2:c" |], result)
+
+[<Test>]
+let ``AsyncSeq.zipWithIndexAsync on empty sequence returns empty`` () =
+  let result =
+    AsyncSeq.empty<string>
+    |> AsyncSeq.zipWithIndexAsync (fun i x -> async { return sprintf "%d:%s" i x })
+    |> AsyncSeq.toArrayAsync
+    |> Async.RunSynchronously
+  Assert.AreEqual([||], result)
+
+[<Test>]
+let ``AsyncSeq.zipWithIndexAsync matches mapiAsync behavior`` () =
+  let xs = AsyncSeq.ofSeq [10; 20; 30]
+  let f i x = async { return int i * x }
+  let viaZipWithIndexAsync = xs |> AsyncSeq.zipWithIndexAsync f |> AsyncSeq.toArrayAsync |> Async.RunSynchronously
+  let viaMapiAsync = xs |> AsyncSeq.mapiAsync f |> AsyncSeq.toArrayAsync |> Async.RunSynchronously
+  Assert.AreEqual(viaMapiAsync, viaZipWithIndexAsync)
+
+#if (NETSTANDARD2_1 || NETCOREAPP3_0)
+// ===== ofIQueryable =====
+
+/// Minimal IQueryable<'T> implementation that also implements IAsyncEnumerable<'T>,
+/// as required by AsyncSeq.ofIQueryable (which casts its input to IAsyncEnumerable<'T>).
+type private FakeAsyncQueryable<'T>(data: 'T[]) =
+  let inner = data.AsQueryable()
+  interface System.Collections.IEnumerable with
+    member _.GetEnumerator() : System.Collections.IEnumerator = (inner :> System.Collections.IEnumerable).GetEnumerator()
+  interface Collections.Generic.IEnumerable<'T> with
+    member _.GetEnumerator() : Collections.Generic.IEnumerator<'T> = (inner :> Collections.Generic.IEnumerable<'T>).GetEnumerator()
+  interface Linq.IQueryable<'T> with
+    member _.ElementType = inner.ElementType
+    member _.Expression = inner.Expression
+    member _.Provider = inner.Provider
+  interface Collections.Generic.IAsyncEnumerable<'T> with
+    member _.GetAsyncEnumerator(_ct: CancellationToken) : Collections.Generic.IAsyncEnumerator<'T> =
+      let e = (data :> Collections.Generic.IEnumerable<'T>).GetEnumerator()
+      { new Collections.Generic.IAsyncEnumerator<'T> with
+          member _.Current = e.Current
+          member _.MoveNextAsync() = Threading.Tasks.ValueTask<bool>(e.MoveNext())
+          member _.DisposeAsync() = e.Dispose(); Threading.Tasks.ValueTask() }
+
+[<Test>]
+let ``AsyncSeq.ofIQueryable returns elements in order`` () =
+  let query = FakeAsyncQueryable<int>([| 1; 2; 3 |]) :> Linq.IQueryable<int>
+  let result = AsyncSeq.ofIQueryable query |> AsyncSeq.toArrayAsync |> Async.RunSynchronously
+  Assert.AreEqual([| 1; 2; 3 |], result)
+
+[<Test>]
+let ``AsyncSeq.ofIQueryable on empty queryable returns empty`` () =
+  let query = FakeAsyncQueryable<int>([||]) :> Linq.IQueryable<int>
+  let result = AsyncSeq.ofIQueryable query |> AsyncSeq.toArrayAsync |> Async.RunSynchronously
+  Assert.AreEqual([||], result)
+#endif