diff --git a/src/Daqifi.Core.Tests/Daqifi.Core.Tests.csproj b/src/Daqifi.Core.Tests/Daqifi.Core.Tests.csproj
index a398292..5d29885 100644
--- a/src/Daqifi.Core.Tests/Daqifi.Core.Tests.csproj
+++ b/src/Daqifi.Core.Tests/Daqifi.Core.Tests.csproj
@@ -12,11 +12,11 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="coverlet.msbuild" Version="6.0.4">
+    <PackageReference Include="coverlet.msbuild" Version="8.0.1">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="coverlet.collector" Version="6.0.4" />
+    <PackageReference Include="coverlet.collector" Version="8.0.1" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.3.0" />
     <PackageReference Include="xunit" Version="2.9.3" />
     <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5" />
diff --git a/src/Daqifi.Core.Tests/Device/SdCard/SdCardCsvFileParserTests.cs b/src/Daqifi.Core.Tests/Device/SdCard/SdCardCsvFileParserTests.cs
index 5bbf24a..246dd20 100644
--- a/src/Daqifi.Core.Tests/Device/SdCard/SdCardCsvFileParserTests.cs
+++ b/src/Daqifi.Core.Tests/Device/SdCard/SdCardCsvFileParserTests.cs
@@ -447,7 +447,7 @@ public async Task ParseAsync_ProgressReporting_CallsCallback()
         var parser = new global::Daqifi.Core.Device.SdCard.SdCardCsvFileParser();
         var options = new global::Daqifi.Core.Device.SdCard.SdCardParseOptions
         {
-            Progress = new Progress<global::Daqifi.Core.Device.SdCard.SdCardParseProgress>(p =>
+            Progress = new SynchronousProgress<global::Daqifi.Core.Device.SdCard.SdCardParseProgress>(p =>
             {
                 progressCalls++;
                 lastProgress = p;
diff --git a/src/Daqifi.Core.Tests/Device/SdCard/SdCardFileParserTests.cs b/src/Daqifi.Core.Tests/Device/SdCard/SdCardFileParserTests.cs
index 2f3c946..2600f39 100644
--- a/src/Daqifi.Core.Tests/Device/SdCard/SdCardFileParserTests.cs
+++ b/src/Daqifi.Core.Tests/Device/SdCard/SdCardFileParserTests.cs
@@ -485,7 +485,7 @@ public async Task ParseAsync_ReportsProgressMonotonically()
         var progressReports = new List<SdCardParseProgress>();
         var options = new SdCardParseOptions
         {
-            Progress = new Progress<SdCardParseProgress>(p => progressReports.Add(p))
+            Progress = new SynchronousProgress<SdCardParseProgress>(p => progressReports.Add(p))
         };
 
         // Act
@@ -493,9 +493,6 @@ public async Task ParseAsync_ReportsProgressMonotonically()
         // Enumerate samples to force full parse
         await ToListAsync(session.Samples);
 
-        // Allow progress handler to execute (Progress<T> posts to SynchronizationContext)
-        await Task.Delay(100);
-
         // Assert — at least one progress report
         Assert.NotEmpty(progressReports);
 
diff --git a/src/Daqifi.Core.Tests/Device/SdCard/SdCardFileReceiverTests.cs b/src/Daqifi.Core.Tests/Device/SdCard/SdCardFileReceiverTests.cs
index 1d479f7..516a703 100644
--- a/src/Daqifi.Core.Tests/Device/SdCard/SdCardFileReceiverTests.cs
+++ b/src/Daqifi.Core.Tests/Device/SdCard/SdCardFileReceiverTests.cs
@@ -115,14 +115,11 @@ public async Task ReceiveAsync_ProgressReporting_BytesReceivedIncreases()
         var receiver = new SdCardFileReceiver(sourceStream, bufferSize: 100);
 
         var progressReports = new System.Collections.Generic.List<SdCardTransferProgress>();
-        var progress = new Progress<SdCardTransferProgress>(p => progressReports.Add(p));
+        var progress = new SynchronousProgress<SdCardTransferProgress>(p => progressReports.Add(p));
 
         // Act
         await receiver.ReceiveAsync(destinationStream, "test.bin", progress);
 
-        // Allow progress callbacks to fire (they're posted to the sync context)
-        await Task.Delay(100);
-
         // Assert — we should have received at least one progress report
         Assert.NotEmpty(progressReports);
         Assert.All(progressReports, p =>
diff --git a/src/Daqifi.Core.Tests/Device/SdCard/SdCardJsonFileParserTests.cs b/src/Daqifi.Core.Tests/Device/SdCard/SdCardJsonFileParserTests.cs
index 3dedca8..d3ec598 100644
--- a/src/Daqifi.Core.Tests/Device/SdCard/SdCardJsonFileParserTests.cs
+++ b/src/Daqifi.Core.Tests/Device/SdCard/SdCardJsonFileParserTests.cs
@@ -253,15 +253,16 @@ public async Task ParseAsync_ProgressReporting_CallsCallback()
         );
 
         var progressCalls = 0;
+        var lastProgress = default(global::Daqifi.Core.Device.SdCard.SdCardParseProgress);
         var parser = new global::Daqifi.Core.Device.SdCard.SdCardJsonFileParser();
         var options = new global::Daqifi.Core.Device.SdCard.SdCardParseOptions
         {
             FallbackTimestampFrequency = 100,
-            Progress = new Progress<global::Daqifi.Core.Device.SdCard.SdCardParseProgress>(p =>
+            Progress = new SynchronousProgress<global::Daqifi.Core.Device.SdCard.SdCardParseProgress>(p =>
             {
                 progressCalls++;
+                lastProgress = p;
                 Assert.True(p.BytesRead >= 0);
-                Assert.Equal(250, p.MessagesRead);
             })
         };
 
@@ -272,6 +273,7 @@ public async Task ParseAsync_ProgressReporting_CallsCallback()
         // Assert
         Assert.Equal(250, samples.Count);
         Assert.True(progressCalls >= 2);  // At least 2 progress updates (100-line batches + final)
+        Assert.Equal(250, lastProgress.MessagesRead);
     }
 
     [Fact]
diff --git a/src/Daqifi.Core.Tests/Device/SdCard/SynchronousProgress.cs b/src/Daqifi.Core.Tests/Device/SdCard/SynchronousProgress.cs
new file mode 100644
index 0000000..9a4245e
--- /dev/null
+++ b/src/Daqifi.Core.Tests/Device/SdCard/SynchronousProgress.cs
@@ -0,0 +1,13 @@
+using System;
+
+namespace Daqifi.Core.Tests.Device.SdCard;
+
+/// <summary>
+/// A synchronous <see cref="IProgress{T}"/> implementation for tests.
+/// Unlike <see cref="Progress{T}"/>, this invokes the callback inline on the
+/// calling thread, avoiding race conditions in assertions.
+/// </summary>
+internal sealed class SynchronousProgress<T>(Action<T> handler) : IProgress<T>
+{
+    public void Report(T value) => handler(value);
+}