diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e4fa3d1..42adc09 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -17,7 +17,7 @@ jobs:
   build-and-test:
     name: ${{ matrix.os }}
     runs-on: ${{ matrix.os }}
-    timeout-minutes: 10
+    timeout-minutes: 15
     strategy:
       fail-fast: false
       matrix:
diff --git a/test/Pants.Tests/Cloud/PantsCloudCrashRecoveryTests.cs b/test/Pants.Tests/Cloud/PantsCloudCrashRecoveryTests.cs
index 41a52ab..b2f3cda 100644
--- a/test/Pants.Tests/Cloud/PantsCloudCrashRecoveryTests.cs
+++ b/test/Pants.Tests/Cloud/PantsCloudCrashRecoveryTests.cs
@@ -331,7 +331,8 @@ static async Task WaitForChildReadinessAsync(Process child, string databasePath)
         var readyPath = Path.Combine(databasePath, ReadyFileName);
         while (!File.Exists(readyPath))
         {
-            if (child.HasExited)
+            // The child can publish readiness and exit between these two observations.
+            if (child.HasExited && !File.Exists(readyPath))
             {
                 throw new XunitException(
                     $"Crash child exited with code {child.ExitCode} before readiness.");
diff --git a/test/Pants.Tests/Observability/PantsWalDurabilityMetricsTests.cs b/test/Pants.Tests/Observability/PantsWalDurabilityMetricsTests.cs
index f5e791f..d745bf3 100644
--- a/test/Pants.Tests/Observability/PantsWalDurabilityMetricsTests.cs
+++ b/test/Pants.Tests/Observability/PantsWalDurabilityMetricsTests.cs
@@ -290,10 +290,8 @@ public async Task ShouldMeasureAppendAndFsyncAtSeparatePhysicalBoundaries()
 
         var metrics = await database.Diagnostics.GetRuntimeMetricsAsync();
         Assert.True(metrics.WalAppendNanosecondsTotal >= 50_000_000);
-        Assert.True(
-            metrics.WalFsyncNanosecondsTotal < metrics.WalAppendNanosecondsTotal,
-            $"Expected fsync {metrics.WalFsyncNanosecondsTotal} ns to exclude " +
-            $"the delayed append {metrics.WalAppendNanosecondsTotal} ns.");
+        Assert.Equal(1, metrics.WalFsyncCount);
+        Assert.InRange(metrics.WalFsyncNanosecondsTotal, 1, failpoints.FsyncWindowNanoseconds);
     }
 
     static async ValueTask CommitAsync(
diff --git a/test/Pants.Tests/Observability/WalAppendDelayFailpointHandler.cs b/test/Pants.Tests/Observability/WalAppendDelayFailpointHandler.cs
index 4ce8d80..06942f3 100644
--- a/test/Pants.Tests/Observability/WalAppendDelayFailpointHandler.cs
+++ b/test/Pants.Tests/Observability/WalAppendDelayFailpointHandler.cs
@@ -1,12 +1,27 @@
+using System.Diagnostics;
+
 namespace Cntryl.Pants.Observability;
 
 sealed class WalAppendDelayFailpointHandler(TimeSpan delay) : IFailpointHandler
 {
+    long _flushStarted;
+
+    public long FsyncWindowNanoseconds { get; private set; }
+
     public void Hit(Failpoint failpoint)
     {
         if (failpoint == Failpoint.MidWalAppend)
         {
             Thread.Sleep(delay);
         }
+
+        if (failpoint == Failpoint.BeforeWalFlush)
+        {
+            _flushStarted = Stopwatch.GetTimestamp();
+        }
+        else if (failpoint == Failpoint.AfterWalFlush)
+        {
+            FsyncWindowNanoseconds = checked(Stopwatch.GetElapsedTime(_flushStarted).Ticks * 100);
+        }
     }
 }
diff --git a/test/Pants.Tests/Runtime/PantsBackgroundFlushPipelineTests.cs b/test/Pants.Tests/Runtime/PantsBackgroundFlushPipelineTests.cs
index 8007a1a..9c117a2 100644
--- a/test/Pants.Tests/Runtime/PantsBackgroundFlushPipelineTests.cs
+++ b/test/Pants.Tests/Runtime/PantsBackgroundFlushPipelineTests.cs
@@ -2623,7 +2623,7 @@ await CommitAsync(
                     {
                         Assert.True(await database.Maintenance.WaitForWriteStallClearAsync(
                             family,
-                            AssertionTimeout));
+                            BackgroundWorkTimeout));
                     }
                 }
             }
@@ -2651,7 +2651,7 @@ async Task ReadLayoutAsync()
         // legitimately take longer than five seconds while eight 132 KiB writes are flushed
         // alongside repeated manifest reads.
         await Task.WhenAll(work).WaitAsync(BackgroundWorkTimeout);
-        await database.Maintenance.FlushAsync(family).AsTask().WaitAsync(AssertionTimeout);
+        await database.Maintenance.FlushAsync(family).AsTask().WaitAsync(BackgroundWorkTimeout);
 
         var layout = await database.Diagnostics.GetStorageLayoutAsync();
         var names = layout.Levels.SelectMany(static level => level.Files)
diff --git a/test/Pants.Tests/Storage/PantsDiskResidentDifferentialTests.cs b/test/Pants.Tests/Storage/PantsDiskResidentDifferentialTests.cs
index 0af2018..ca994e8 100644
--- a/test/Pants.Tests/Storage/PantsDiskResidentDifferentialTests.cs
+++ b/test/Pants.Tests/Storage/PantsDiskResidentDifferentialTests.cs
@@ -312,7 +312,8 @@ static async Task WaitForCrashChildAsync(Process child, string path)
         var readyPath = Path.Combine(path, CrashReadyFileName);
         while (!File.Exists(readyPath))
         {
-            if (child.HasExited)
+            // The child can publish readiness and exit between these two observations.
+            if (child.HasExited && !File.Exists(readyPath))
             {
                 throw new XunitException(
                     $"Differential crash child exited with {child.ExitCode} before readiness.");
diff --git a/test/Pants.Tests/Transactions/PantsCommitCoalescingCrashRecoveryTests.cs b/test/Pants.Tests/Transactions/PantsCommitCoalescingCrashRecoveryTests.cs
index fa22ee2..1ea83f9 100644
--- a/test/Pants.Tests/Transactions/PantsCommitCoalescingCrashRecoveryTests.cs
+++ b/test/Pants.Tests/Transactions/PantsCommitCoalescingCrashRecoveryTests.cs
@@ -366,7 +366,8 @@ static async Task WaitForChildReadinessAsync(Process child, string databasePath)
         {
             while (!File.Exists(readyPath))
             {
-                if (child.HasExited)
+                // The child can publish readiness and exit between these two observations.
+                if (child.HasExited && !File.Exists(readyPath))
                 {
                     throw new XunitException(
                         $"Coalesced-commit crash child exited with code {child.ExitCode} " +
diff --git a/test/Pants.Tests/Transactions/Spill/PantsTransactionSpillCrashRecoveryTests.cs b/test/Pants.Tests/Transactions/Spill/PantsTransactionSpillCrashRecoveryTests.cs
index 9ba3f8b..45b847e 100644
--- a/test/Pants.Tests/Transactions/Spill/PantsTransactionSpillCrashRecoveryTests.cs
+++ b/test/Pants.Tests/Transactions/Spill/PantsTransactionSpillCrashRecoveryTests.cs
@@ -177,7 +177,8 @@ static async Task WaitForChildReadinessAsync(Process child, string databasePath)
         {
             while (!File.Exists(readyPath))
             {
-                if (child.HasExited)
+                // The child can publish readiness and exit between these two observations.
+                if (child.HasExited && !File.Exists(readyPath))
                 {
                     throw new XunitException(
                         $"Transaction spill crash child exited with code {child.ExitCode} before readiness.");