diff --git a/Generation/Converters/Argumentum.AssetConverter.Tests/Ontology/OwlAdapterRegressionTests.cs b/Generation/Converters/Argumentum.AssetConverter.Tests/Ontology/OwlAdapterRegressionTests.cs
index 78d734f4..a1a5d454 100644
--- a/Generation/Converters/Argumentum.AssetConverter.Tests/Ontology/OwlAdapterRegressionTests.cs
+++ b/Generation/Converters/Argumentum.AssetConverter.Tests/Ontology/OwlAdapterRegressionTests.cs
@@ -303,7 +303,7 @@ public void DocumentConcept_Unknown_Type_Throws()
         }
 
         [Fact]
-        public void ToFileAsync_Writes_A_Non_Empty_OWL2XML_File()
+        public async Task ToFileAsync_Writes_A_Non_Empty_OWL2XML_File()
         {
             // Serialization works end-to-end (this is why #133 ships a non-empty ontology despite
             // the readers being broken — the graph is correctly built, only self-retrieval fails).
@@ -316,7 +316,7 @@ public void ToFileAsync_Writes_A_Non_Empty_OWL2XML_File()
             var tempPath = Path.Combine(Path.GetTempPath(), $"arg_onto_test_{Guid.NewGuid():N}.owl");
             try
             {
-                adapter.ToFileAsync(OWLSharp.OWLEnums.OWLFormats.OWL2XML, tempPath).Wait();
+                await adapter.ToFileAsync(OWLSharp.OWLEnums.OWLFormats.OWL2XML, tempPath);
                 File.Exists(tempPath).Should().BeTrue();
                 var content = File.ReadAllText(tempPath);
                 content.Should().NotBeNullOrEmpty("the serialized ontology must be non-empty");
diff --git a/Generation/Converters/Argumentum.AssetConverter.Tests/WebBasedGenerator/HarvestManagerExpectedImageCountTests.cs b/Generation/Converters/Argumentum.AssetConverter.Tests/WebBasedGenerator/HarvestManagerExpectedImageCountTests.cs
index b0b44766..2a1671d9 100644
--- a/Generation/Converters/Argumentum.AssetConverter.Tests/WebBasedGenerator/HarvestManagerExpectedImageCountTests.cs
+++ b/Generation/Converters/Argumentum.AssetConverter.Tests/WebBasedGenerator/HarvestManagerExpectedImageCountTests.cs
@@ -54,7 +54,7 @@ public class HarvestManagerExpectedImageCountTests
         [InlineData(10, 3, "BUNCH", 10)]  // case-sensitive: CardPen rsstyle is lowercase; "BUNCH" does NOT group
         [InlineData(10, 3, "Bunch", 10)]  // case-sensitive: mixed-case does NOT group either
         public void ComputeExpectedImageCount_MirrorsCardPenGrouping(
-            int cardCount, int rscount, string rsstyle, int expected)
+            int cardCount, int rscount, string? rsstyle, int expected)
         {
             HarvestManager.ComputeExpectedImageCount(cardCount, rscount, rsstyle)
                 .Should().Be(expected,
diff --git a/Generation/Converters/Argumentum.AssetConverter.Tests/WebBasedGenerator/LocalizedFileNameContractTests.cs b/Generation/Converters/Argumentum.AssetConverter.Tests/WebBasedGenerator/LocalizedFileNameContractTests.cs
index b6562545..5f1f15f7 100644
--- a/Generation/Converters/Argumentum.AssetConverter.Tests/WebBasedGenerator/LocalizedFileNameContractTests.cs
+++ b/Generation/Converters/Argumentum.AssetConverter.Tests/WebBasedGenerator/LocalizedFileNameContractTests.cs
@@ -27,7 +27,7 @@ public class LocalizedFileNameContractTests
         [Theory]
         [InlineData(null)]
         [InlineData("")]
-        public void EmptyOrNull_ReturnedAsIs(string fileName)
+        public void EmptyOrNull_ReturnedAsIs(string? fileName)
         {
             // The first guard returns the input verbatim, so no language substitution is attempted.
             CardSetLocalization.GetLocalizedFileName(fileName, "fr", "en")