diff --git a/test/DemaConsulting.SpdxTool.Tests/DemaConsulting.SpdxTool.Tests.csproj b/test/DemaConsulting.SpdxTool.Tests/DemaConsulting.SpdxTool.Tests.csproj
index 10e9187..c55d290 100644
--- a/test/DemaConsulting.SpdxTool.Tests/DemaConsulting.SpdxTool.Tests.csproj
+++ b/test/DemaConsulting.SpdxTool.Tests/DemaConsulting.SpdxTool.Tests.csproj
@@ -2,7 +2,7 @@
 
 	<PropertyGroup>
 		<TargetFrameworks>net8.0;net9.0;net10.0</TargetFrameworks>
-        <LangVersion>12</LangVersion>
+		<LangVersion>12</LangVersion>
 		<ImplicitUsings>enable</ImplicitUsings>
 		<Nullable>enable</Nullable>
 
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestAddPackage.cs b/test/DemaConsulting.SpdxTool.Tests/TestAddPackage.cs
index be69706..f01d18a 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestAddPackage.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestAddPackage.cs
@@ -44,7 +44,7 @@ public void AddPackage_CommandLine()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "'add-package' command is only valid in a workflow");
+        Assert.Contains("'add-package' command is only valid in a workflow", output);
     }
 
     /// <summary>
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestAddRelationship.cs b/test/DemaConsulting.SpdxTool.Tests/TestAddRelationship.cs
index 8231ed8..163e170 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestAddRelationship.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestAddRelationship.cs
@@ -81,7 +81,7 @@ public void AddRelationship_MissingArguments()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "'add-relationship' command missing arguments");
+        Assert.Contains("'add-relationship' command missing arguments", output);
     }
 
     /// <summary>
@@ -103,7 +103,7 @@ public void AddRelationship_MissingFile()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "File not found: missing.spdx.json");
+        Assert.Contains("File not found: missing.spdx.json", output);
     }
 
     /// <summary>
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestCopyPackage.cs b/test/DemaConsulting.SpdxTool.Tests/TestCopyPackage.cs
index b03cbb8..0ce507f 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestCopyPackage.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestCopyPackage.cs
@@ -44,7 +44,7 @@ public void CopyPackage_MissingArguments()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "'copy-package' command missing arguments");
+        Assert.Contains("'copy-package' command missing arguments", output);
     }
 
     /// <summary>
@@ -65,7 +65,7 @@ public void CopyPackage_MissingFile()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "File not found: missing.spdx.json");
+        Assert.Contains("File not found: missing.spdx.json", output);
     }
 
     /// <summary>
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestFindPackage.cs b/test/DemaConsulting.SpdxTool.Tests/TestFindPackage.cs
index ccf3dfc..66b8483 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestFindPackage.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestFindPackage.cs
@@ -84,7 +84,7 @@ public void FindPackage_MissingArguments()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "'find-package' command missing arguments");
+        Assert.Contains("'find-package' command missing arguments", output);
     }
 
     /// <summary>
@@ -104,7 +104,7 @@ public void FindPackage_MissingFile()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "File not found: missing.spdx.json");
+        Assert.Contains("File not found: missing.spdx.json", output);
     }
 
     /// <summary>
@@ -129,7 +129,7 @@ public void FindPackage_CommandLine()
 
             // Assert: Verify package ID
             Assert.AreEqual(0, exitCode);
-            StringAssert.Contains(output, "SPDXRef-Package-2");
+            Assert.Contains("SPDXRef-Package-2", output);
         }
         finally
         {
@@ -174,7 +174,7 @@ public void FindPackage_ByName()
 
             // Assert: Verify package ID
             Assert.AreEqual(0, exitCode);
-            StringAssert.Contains(output, "Found package SPDXRef-Package-1");
+            Assert.Contains("Found package SPDXRef-Package-1", output);
         }
         finally
         {
@@ -220,7 +220,7 @@ public void FindPackage_ByVersion()
 
             // Assert: Verify package ID
             Assert.AreEqual(0, exitCode);
-            StringAssert.Contains(output, "Found package SPDXRef-Package-2");
+            Assert.Contains("Found package SPDXRef-Package-2", output);
         }
         finally
         {
@@ -266,7 +266,7 @@ public void FindPackage_ByFileName()
 
             // Assert: Verify package ID
             Assert.AreEqual(0, exitCode);
-            StringAssert.Contains(output, "Found package SPDXRef-Package-1");
+            Assert.Contains("Found package SPDXRef-Package-1", output);
         }
         finally
         {
@@ -312,7 +312,7 @@ public void FindPackage_ByDownload()
 
             // Assert: Verify package ID
             Assert.AreEqual(0, exitCode);
-            StringAssert.Contains(output, "Found package SPDXRef-Package-2");
+            Assert.Contains("Found package SPDXRef-Package-2", output);
         }
         finally
         {
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestGetVersion.cs b/test/DemaConsulting.SpdxTool.Tests/TestGetVersion.cs
index 7417534..1ca82d6 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestGetVersion.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestGetVersion.cs
@@ -84,7 +84,7 @@ public void GetVersion_MissingArguments()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "'get-version' command missing arguments");
+        Assert.Contains("'get-version' command missing arguments", output);
     }
 
     /// <summary>
@@ -104,7 +104,7 @@ public void GetVersion_MissingFile()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "File not found: missing.spdx.json");
+        Assert.Contains("File not found: missing.spdx.json", output);
     }
 
     /// <summary>
@@ -129,7 +129,7 @@ public void GetVersion_CommandLine()
 
             // Assert: Verify package ID
             Assert.AreEqual(0, exitCode);
-            StringAssert.Contains(output, "2.0.0");
+            Assert.Contains("2.0.0", output);
         }
         finally
         {
@@ -174,7 +174,7 @@ public void GetVersion_Workflow()
 
             // Assert: Verify package ID
             Assert.AreEqual(0, exitCode);
-            StringAssert.Contains(output, "Found version 2.0.0");
+            Assert.Contains("Found version 2.0.0", output);
         }
         finally
         {
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestHash.cs b/test/DemaConsulting.SpdxTool.Tests/TestHash.cs
index 4d0c1c6..1eadf67 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestHash.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestHash.cs
@@ -41,7 +41,7 @@ public void HashCommand_MissingArguments()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "'hash' command missing arguments");
+        Assert.Contains("'hash' command missing arguments", output);
     }
 
     /// <summary>
@@ -62,7 +62,7 @@ public void HashCommand_MissingFile()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "Error: Could not find file 'missing-file.txt'");
+        Assert.Contains("Error: Could not find file 'missing-file.txt'", output);
     }
 
     /// <summary>
@@ -119,7 +119,7 @@ public void HashCommand_Verify_MissingFile()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "Error: Could not find file");
+        Assert.Contains("Error: Could not find file", output);
     }
 
     /// <summary>
@@ -146,7 +146,7 @@ public void HashCommand_Verify_Bad()
 
             // Assert: Verify error reported
             Assert.AreEqual(1, exitCode);
-            StringAssert.Contains(output, "Sha256 hash mismatch for 'test.txt'");
+            Assert.Contains("Sha256 hash mismatch for 'test.txt'", output);
         }
         finally
         {
@@ -179,7 +179,7 @@ public void HashCommand_Verify_Good()
 
             // Assert: Verify success reported
             Assert.AreEqual(0, exitCode);
-            StringAssert.Contains(output, "Sha256 Digest OK for 'test.txt'");
+            Assert.Contains("Sha256 Digest OK for 'test.txt'", output);
         }
         finally
         {
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestHelp.cs b/test/DemaConsulting.SpdxTool.Tests/TestHelp.cs
index 98613c7..7ae9361 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestHelp.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestHelp.cs
@@ -41,7 +41,7 @@ public void Help_MissingArguments()
 
         // Assert: Verify an error was detected
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "'help' command missing arguments");
+        Assert.Contains("'help' command missing arguments", output);
     }
 
     /// <summary>
@@ -60,7 +60,7 @@ public void Help_UnknownCommand()
 
         // Assert: Verify an error was detected
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "Unknown command: 'unknown-command'");
+        Assert.Contains("Unknown command: 'unknown-command'", output);
     }
 
     /// <summary>
@@ -79,6 +79,6 @@ public void Help_RunWorkflow()
 
         // Assert: Verify success
         Assert.AreEqual(0, exitCode);
-        StringAssert.Contains(output, "This command runs the steps specified in the workflow file/url.");
+        Assert.Contains("This command runs the steps specified in the workflow file/url.", output);
     }
 }
\ No newline at end of file
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestLog.cs b/test/DemaConsulting.SpdxTool.Tests/TestLog.cs
index 6109366..e302bf1 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestLog.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestLog.cs
@@ -50,7 +50,7 @@ public void Log_Short()
 
             // Assert: Verify the log contains the usage information
             var log = File.ReadAllText("output.log");
-            StringAssert.Contains(log, "Usage: spdx-tool");
+            Assert.Contains("Usage: spdx-tool", log);
         }
         finally
         {
@@ -83,7 +83,7 @@ public void Log_Long()
 
             // Assert: Verify the log contains the usage information
             var log = File.ReadAllText("output.log");
-            StringAssert.Contains(log, "Usage: spdx-tool");
+            Assert.Contains("Usage: spdx-tool", log);
         }
         finally
         {
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestPrint.cs b/test/DemaConsulting.SpdxTool.Tests/TestPrint.cs
index 5dfb036..ec1c355 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestPrint.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestPrint.cs
@@ -42,7 +42,7 @@ public void Print_CommandLine()
 
         // Assert: Verify output
         Assert.AreEqual(0, exitCode);
-        StringAssert.Contains(output, "Hello, World!");
+        Assert.Contains("Hello, World!", output);
     }
 
     /// <summary>
@@ -81,8 +81,8 @@ public void Print_Workflow()
 
             // Assert: Verify success
             Assert.AreEqual(0, exitCode);
-            StringAssert.Contains(output, "The first parameter is Hello.");
-            StringAssert.Contains(output, "World is the second parameter.");
+            Assert.Contains("The first parameter is Hello.", output);
+            Assert.Contains("World is the second parameter.", output);
         }
         finally
         {
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestQuery.cs b/test/DemaConsulting.SpdxTool.Tests/TestQuery.cs
index 6fc4d38..40c89fb 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestQuery.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestQuery.cs
@@ -50,7 +50,7 @@ public void Query_MissingArguments()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "'query' command missing arguments");
+        Assert.Contains("'query' command missing arguments", output);
     }
 
     /// <summary>
@@ -71,7 +71,7 @@ public void Query_BadPattern()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "Pattern must contain a 'value' capture group");
+        Assert.Contains("Pattern must contain a 'value' capture group", output);
     }
 
     /// <summary>
@@ -91,7 +91,7 @@ public void Query_InvalidProgram()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "Unable to start program 'does-not-exist'");
+        Assert.Contains("Unable to start program 'does-not-exist'", output);
     }
 
     /// <summary>
@@ -112,7 +112,7 @@ public void Query_DotNet_CommandLine()
 
         // Assert: Verify error reported
         Assert.AreEqual(0, exitCode);
-        StringAssert.Matches(output, VersionRegex());
+        Assert.MatchesRegex(VersionRegex(), output);
     }
 
     /// <summary>
@@ -157,7 +157,7 @@ public void Query_DotNet_Workflow()
 
             // Assert: Verify success
             Assert.AreEqual(0, exitCode);
-            StringAssert.Matches(output, VersionRegex());
+            Assert.MatchesRegex(VersionRegex(), output);
         }
         finally
         {
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestRenameId.cs b/test/DemaConsulting.SpdxTool.Tests/TestRenameId.cs
index b1cde3d..2e1f584 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestRenameId.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestRenameId.cs
@@ -43,7 +43,7 @@ public void RenameId_MissingArguments()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "'rename-id' command missing arguments");
+        Assert.Contains("'rename-id' command missing arguments", output);
     }
 
     /// <summary>
@@ -64,7 +64,7 @@ public void RenameId_MissingFile()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "File not found: missing.spdx.json");
+        Assert.Contains("File not found: missing.spdx.json", output);
     }
 
     /// <summary>
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestRunWorkflow.cs b/test/DemaConsulting.SpdxTool.Tests/TestRunWorkflow.cs
index 7dc9b3e..ae6bff6 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestRunWorkflow.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestRunWorkflow.cs
@@ -50,7 +50,7 @@ public void RunWorkflow_MissingArguments()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "'run-workflow' command missing arguments");
+        Assert.Contains("'run-workflow' command missing arguments", output);
     }
 
     /// <summary>
@@ -69,7 +69,7 @@ public void RunWorkflow_MissingFile()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "File not found: does-not-exist.yaml");
+        Assert.Contains("File not found: does-not-exist.yaml", output);
     }
 
     /// <summary>
@@ -96,7 +96,7 @@ public void RunWorkflow_FileInvalid()
 
             // Assert: Verify error reported
             Assert.AreEqual(1, exitCode);
-            StringAssert.Contains(output, "Error: Workflow invalid.yaml missing steps");
+            Assert.Contains("Error: Workflow invalid.yaml missing steps", output);
         }
         finally
         {
@@ -132,7 +132,7 @@ public void RunWorkflow_MissingParameterInFile()
 
             // Assert: Verify error reported
             Assert.AreEqual(1, exitCode);
-            StringAssert.Contains(output, "'help' command missing 'about' input");
+            Assert.Contains("'help' command missing 'about' input", output);
         }
         finally
         {
@@ -170,8 +170,8 @@ public void RunWorkflow()
 
             // Assert: Verify success
             Assert.AreEqual(0, exitCode);
-            StringAssert.Contains(output,
-                "This command displays extended help information about the specified command");
+            Assert.Contains("This command displays extended help information about the specified command",
+output);
         }
         finally
         {
@@ -212,8 +212,8 @@ public void RunWorkflow_WithDefaultParameters()
 
             // Assert: Verify success
             Assert.AreEqual(0, exitCode);
-            StringAssert.Contains(output,
-                "This command displays extended help information about the specified command");
+            Assert.Contains("This command displays extended help information about the specified command",
+output);
         }
         finally
         {
@@ -255,7 +255,7 @@ public void RunWorkflow_WithSpecifiedParameters()
 
             // Assert: Verify success
             Assert.AreEqual(0, exitCode);
-            StringAssert.Contains(output, "This command produces a Markdown summary of an SPDX document");
+            Assert.Contains("This command produces a Markdown summary of an SPDX document", output);
         }
         finally
         {
@@ -319,7 +319,7 @@ public void RunWorkflow_WithOutputs()
 
             // Assert: Verify success
             Assert.AreEqual(0, exitCode);
-            StringAssert.Contains(output, "Output is Got Fred Param");
+            Assert.Contains("Output is Got Fred Param", output);
         }
         finally
         {
@@ -385,7 +385,7 @@ public void RunWorkflow_WithBadIntegrity()
 
             // Assert: Verify success
             Assert.AreEqual(1, exitCode);
-            StringAssert.Contains(output, "Error: Integrity check of workflow2.yaml failed");
+            Assert.Contains("Error: Integrity check of workflow2.yaml failed", output);
         }
         finally
         {
@@ -431,7 +431,7 @@ public void RunWorkflow_Url()
 
             // Assert: Verify success
             Assert.AreEqual(0, exitCode);
-            StringAssert.Matches(output, DotnetVersionRegex());
+            Assert.MatchesRegex(DotnetVersionRegex(), output);
         }
         finally
         {
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestSelfValidation.cs b/test/DemaConsulting.SpdxTool.Tests/TestSelfValidation.cs
index 0186897..612be55 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestSelfValidation.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestSelfValidation.cs
@@ -41,7 +41,7 @@ public void SelfValidation()
 
         // Assert: Verify success
         Assert.AreEqual(0, exitCode);
-        StringAssert.Contains(output, "Validation Passed");
+        Assert.Contains("Validation Passed", output);
     }
 
     /// <summary>
@@ -62,7 +62,7 @@ public void SelfValidation_Depth()
         Assert.AreEqual(0, exitCode);
 
         // Assert: Verify depth of result
-        StringAssert.Contains(output, "### DemaConsulting.SpdxTool");
+        Assert.Contains("### DemaConsulting.SpdxTool", output);
     }
 
     /// <summary>
@@ -92,20 +92,20 @@ public void SelfValidation_TrxResults()
             Assert.IsNotNull(results);
 
             // Assert: Verify the results contain expected content
-            StringAssert.Contains(results, "DemaConsulting.SpdxTool Validation Results -");
-            StringAssert.Contains(results, "SpdxTool_AddPackage");
-            StringAssert.Contains(results, "SpdxTool_AddRelationship");
-            StringAssert.Contains(results, "SpdxTool_CopyPackage");
-            StringAssert.Contains(results, "SpdxTool_FindPackage");
-            StringAssert.Contains(results, "SpdxTool_GetVersion");
-            StringAssert.Contains(results, "SpdxTool_Query");
-            StringAssert.Contains(results, "SpdxTool_RenameId");
-            StringAssert.Contains(results, "SpdxTool_UpdatePackage");
-            StringAssert.Contains(results, """
+            Assert.Contains("DemaConsulting.SpdxTool Validation Results -", results);
+            Assert.Contains("SpdxTool_AddPackage", results);
+            Assert.Contains("SpdxTool_AddRelationship", results);
+            Assert.Contains("SpdxTool_CopyPackage", results);
+            Assert.Contains("SpdxTool_FindPackage", results);
+            Assert.Contains("SpdxTool_GetVersion", results);
+            Assert.Contains("SpdxTool_Query", results);
+            Assert.Contains("SpdxTool_RenameId", results);
+            Assert.Contains("SpdxTool_UpdatePackage", results);
+            Assert.Contains("""
                                              <ResultSummary outcome="Completed">
                                                <Counters total="8" executed="8" passed="8" failed="0" />
                                              </ResultSummary>
-                                           """);
+                                           """, results);
         }
         finally
         {
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestSetVariable.cs b/test/DemaConsulting.SpdxTool.Tests/TestSetVariable.cs
index 093ba2e..c1d9507 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestSetVariable.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestSetVariable.cs
@@ -41,7 +41,7 @@ public void SetVariable_CommandLine()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "'set-variable' command is only valid in a workflow");
+        Assert.Contains("'set-variable' command is only valid in a workflow", output);
     }
 
     /// <summary>
@@ -83,7 +83,7 @@ public void SetVariable()
 
             // Assert: Verify success
             Assert.AreEqual(0, exitCode);
-            StringAssert.Contains(output, "p1p2 is Hello and World");
+            Assert.Contains("p1p2 is Hello and World", output);
         }
         finally
         {
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestToMarkdown.cs b/test/DemaConsulting.SpdxTool.Tests/TestToMarkdown.cs
index 98bbd16..7e3483c 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestToMarkdown.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestToMarkdown.cs
@@ -41,7 +41,7 @@ public void ToMarkdown_MissingArguments()
 
         // Assert: Verify the conversion failed
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "'to-markdown' command missing arguments");
+        Assert.Contains("'to-markdown' command missing arguments", output);
     }
 
     /// <summary>
@@ -61,7 +61,7 @@ public void ToMarkdown_MissingSpdx()
 
         // Assert: Verify the conversion failed
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "File not found: missing.spdx.json");
+        Assert.Contains("File not found: missing.spdx.json", output);
     }
 
     /// <summary>
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestUnknownCommand.cs b/test/DemaConsulting.SpdxTool.Tests/TestUnknownCommand.cs
index 10241a1..3ebd52b 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestUnknownCommand.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestUnknownCommand.cs
@@ -41,6 +41,6 @@ public void UnknownCommand()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "Error: Unknown command 'unknown-command'");
+        Assert.Contains("Error: Unknown command 'unknown-command'", output);
     }
 }
\ No newline at end of file
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestUpdatePackage.cs b/test/DemaConsulting.SpdxTool.Tests/TestUpdatePackage.cs
index c4e0f85..16088b1 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestUpdatePackage.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestUpdatePackage.cs
@@ -43,7 +43,7 @@ public void UpdatePackage_CommandLine()
 
         // Assert: Verify error reported
         Assert.AreEqual(1, exitCode);
-        StringAssert.Contains(output, "'update-package' command is only valid in a workflow");
+        Assert.Contains("'update-package' command is only valid in a workflow", output);
     }
 
     /// <summary>
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestUsage.cs b/test/DemaConsulting.SpdxTool.Tests/TestUsage.cs
index 24a736d..de97612 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestUsage.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestUsage.cs
@@ -42,8 +42,8 @@ public void Usage_NoArguments()
         Assert.AreEqual(1, exitCode);
 
         // Assert: Verify the output contains the usage information
-        StringAssert.Contains(output, "Error: Missing arguments");
-        StringAssert.Contains(output, "Usage: spdx-tool");
+        Assert.Contains("Error: Missing arguments", output);
+        Assert.Contains("Usage: spdx-tool", output);
     }
 
     /// <summary>
@@ -63,7 +63,7 @@ public void Usage_HelpShort()
         Assert.AreEqual(0, exitCode);
 
         // Assert: Verify the output contains the usage information
-        StringAssert.Contains(output, "Usage: spdx-tool");
+        Assert.Contains("Usage: spdx-tool", output);
     }
 
     /// <summary>
@@ -83,6 +83,6 @@ public void Usage_HelpLong()
         Assert.AreEqual(0, exitCode);
 
         // Assert: Verify the output contains the usage information
-        StringAssert.Contains(output, "Usage: spdx-tool");
+        Assert.Contains("Usage: spdx-tool", output);
     }
 }
\ No newline at end of file
diff --git a/test/DemaConsulting.SpdxTool.Tests/TestVersion.cs b/test/DemaConsulting.SpdxTool.Tests/TestVersion.cs
index 0f4970f..af35d33 100644
--- a/test/DemaConsulting.SpdxTool.Tests/TestVersion.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/TestVersion.cs
@@ -52,7 +52,7 @@ public void Version_Short()
         Assert.AreEqual(0, exitCode);
 
         // Assert: Verify version response
-        StringAssert.Matches(output, VersionRegex());
+        Assert.MatchesRegex(VersionRegex(), output);
     }
 
     /// <summary>
@@ -72,6 +72,6 @@ public void Version_Long()
         Assert.AreEqual(0, exitCode);
 
         // Assert: Verify version response
-        StringAssert.Matches(output, VersionRegex());
+        Assert.MatchesRegex(VersionRegex(), output);
     }
 }
\ No newline at end of file