Put path to TestCases-dir into a constant.

ICSharpCode.Decompiler.Tests/CorrectnessTestRunner.cs

@@ -28,7 +28,7 @@ namespace ICSharpCode.Decompiler.Tests
     [TestFixture]
 	public class CorrectnessTestRunner
 	{
-		const string TestCasePath = @"../../../../ICSharpCode.Decompiler.Tests/TestCases/Correctness";
+		const string TestCasePath = DecompilerTestBase.TestCasePath + "/Correctness";
 
 		[Test]
 		public void AllFilesHaveTests()

ICSharpCode.Decompiler.Tests/DecompilerTestBase.cs

@@ -32,9 +32,11 @@ namespace ICSharpCode.Decompiler.Tests
 {
 	public abstract class DecompilerTestBase
 	{
+		public const string TestCasePath = "../../../TestCases";
+
 		protected static void ValidateFileRoundtrip(string samplesFileName)
 		{
-			var fullPath = Path.Combine(@"../../../../ICSharpCode.Decompiler.Tests", samplesFileName);
+			var fullPath = Path.Combine(TestCasePath, "..", samplesFileName);
 			AssertRoundtripCode(fullPath);
 		}
 

ICSharpCode.Decompiler.Tests/ILPrettyTestRunner.cs

@@ -12,7 +12,7 @@ namespace ICSharpCode.Decompiler.Tests
 {
 	public class ILPrettyTestRunner
 	{
-		const string TestCasePath = @"../../../../ICSharpCode.Decompiler.Tests/TestCases/ILPretty";
+		const string TestCasePath = DecompilerTestBase.TestCasePath + "/ILPretty";
 
 		[Test]
 		public void AllFilesHaveTests()

ICSharpCode.Decompiler.Tests/PrettyTestRunner.cs

@@ -28,7 +28,7 @@ namespace ICSharpCode.Decompiler.Tests
 {
 	public class PrettyTestRunner
 	{
-		const string TestCasePath = @"../../../../ICSharpCode.Decompiler.Tests/TestCases/Pretty";
+		const string TestCasePath = DecompilerTestBase.TestCasePath + "/Pretty";
 
 		[Test]
 		public void AllFilesHaveTests()