Assertions should cause a test failure.

ICSharpCode.Decompiler/Tests/ICSharpCode.Decompiler.Tests.csproj

@@ -136,6 +136,7 @@
     <Compile Include="CorrectnessTestRunner.cs" />
     <Compile Include="TestCases\Pretty\HelloWorld.cs" />
     <Compile Include="TestCases\Pretty\InlineAssignmentTest.cs" />
+    <Compile Include="TestTraceListener.cs" />
     <Compile Include="Util\IntervalTests.cs" />
     <Compile Include="Util\LongSetTests.cs" />
     <Compile Include="CustomAttributes\CustomAttributeTests.cs" />

ICSharpCode.Decompiler/Tests/TestTraceListener.cs

@@ -0,0 +1,47 @@
+// Copyright (c) 2016 Daniel Grunwald
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using System.Diagnostics;
+using NUnit.Core;
+using NUnit.Framework;
+
+namespace ICSharpCode.Decompiler.Tests
+{
+	[SetUpFixture]
+	public class TestTraceListener : DefaultTraceListener
+	{
+		[SetUp]
+		public void RunBeforeAnyTests()
+		{
+			Debug.Listeners.Insert(0, this);
+		}
+		
+		
+		[TearDown]
+		public void RunAfterAnyTests()
+		{
+			Debug.Listeners.Remove(this);
+		}
+		
+		public override void Fail(string message, string detailMessage)
+		{
+			Assert.Fail(message + " " + detailMessage);
+		}
+	}
+}