test: raise Keychain retry budget to stop the macos-15 selection flake

CHANGELOG.md

@@ -21,6 +21,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   still bind the keystore to this machine/user, and the security boundary is
   unchanged (filesystem permissions on the credentials directory).
 
+- **The Keychain test-retry budget is raised so `macos-15` stops flaking.** The
+  `RetryHelper` default was 20 attempts × 25 ms ≈ 500 ms, which was too tight on
+  a contended `macos-15` runner: a selection item written by
+  `RestoreCredentialAsync` was not always visible within it, so
+  `RestoreCredentialAsync_PreservesAccountIdAndSelection` timed out its
+  `IsSelected` retry and the assertion failed intermittently. The default is now
+  40 × 50 ms ≈ 2 s; retries still return as soon as the store is consistent, so
+  passing runs are unaffected. Test-only change.
+
 ### Changed
 
 - **Keystore format bumped to version 2** (`.keystore` header). A version-1

tests/NextIteration.SpectreConsole.Auth.Tests/Infrastructure/RetryHelper.cs

@@ -18,6 +18,15 @@ namespace NextIteration.SpectreConsole.Auth.Tests.Infrastructure
     /// final attempt still fails</b>. A persistent error still fails the test with its real
     /// message; only a transient one is ridden out.
     /// </para>
+    /// <para>
+    /// The default budget is 40 attempts × 50 ms ≈ 2 s. The original 20 × 25 ms ≈ 500 ms
+    /// proved too tight on a contended <c>macos-15</c> runner: a selection item written by
+    /// <c>RestoreCredentialAsync</c> moments earlier was not always visible within it, so
+    /// the <c>IsSelected</c> retry in <c>RestoreCredentialAsync_PreservesAccountIdAndSelection</c>
+    /// timed out and the following assertion failed. Retries return
+    /// as soon as the store is consistent, so a passing run does not pay the ceiling; only a
+    /// genuine failure waits the full 2 s before surfacing.
+    /// </para>
     /// </summary>
     internal static class RetryHelper
     {
@@ -29,8 +38,8 @@ internal static class RetryHelper
         /// </summary>
         internal static async Task<bool> UntilTrueAsync(
             Func<Task<bool>> action,
-            int maxAttempts = 20,
-            int delayMs = 25)
+            int maxAttempts = 40,
+            int delayMs = 50)
         {
             for (var attempt = 1; attempt <= maxAttempts; attempt++)
             {
@@ -69,8 +78,8 @@ internal static async Task<bool> UntilTrueAsync(
         internal static async Task<T> UntilAsync<T>(
             Func<Task<T>> action,
             Func<T, bool> predicate,
-            int maxAttempts = 20,
-            int delayMs = 25)
+            int maxAttempts = 40,
+            int delayMs = 50)
         {
             T result = default!;
             var satisfied = false;