Abstract classes are not shown as nunit test fixtures in test pad.

Fixed StackOverflowError when updating test class members from new compilation unit.

src/AddIns/Analysis/UnitTesting/Src/NUnitTestFramework.cs

@@ -44,6 +44,8 @@ namespace ICSharpCode.UnitTesting
 		/// </summary>
 		public bool IsTestClass(IClass c)
 		{
+			if (c == null) return false;
+			if (c.IsAbstract) return false;
 			StringComparer nameComparer = GetNameComparer(c);
 			if (nameComparer != null) {
 				NUnitTestAttributeName testAttributeName = new NUnitTestAttributeName("TestFixture", nameComparer);

src/AddIns/Analysis/UnitTesting/Src/TestClass.cs

@@ -297,7 +297,7 @@ namespace ICSharpCode.UnitTesting
 			{
 				foreach (var testMember in testFrameworks.GetTestMembersFor(c.BaseClass)) {
 					BaseTestMember baseTestMethod = new BaseTestMember(declaringType, testMember.Member);
-					TestMember testMethod = new TestMember(c, baseTestMethod);
+					TestMember testMethod = new TestMember(c.BaseClass, baseTestMethod);
 					if (testMember.Member.IsVirtual) {
 						if (!testMembers.Contains(testMember.Name)) {
 							testMembers.Add(testMethod);
@@ -313,7 +313,7 @@ namespace ICSharpCode.UnitTesting
 
 			baseClassesFQNames.Clear();
 			foreach (var memberDeclaringClass in testMembers.Select(member => member.DeclaringType).Distinct())
-				if (memberDeclaringClass != declaringType)
+				if (memberDeclaringClass.CompareTo(declaringType) != 0)
 					baseClassesFQNames.Add(memberDeclaringClass.FullyQualifiedName);
 			return testMembers;
 		}

src/AddIns/Analysis/UnitTesting/Test/Frameworks/NUnitTestFrameworkIsTestClassTests.cs

@@ -37,6 +37,14 @@ namespace UnitTesting.Tests.Frameworks
 			Assert.IsTrue(testFramework.IsTestClass(mockClass));
 		}
 		
+		[Test]
+		public void IsTestClassReturnsFalseWhenClassHasTestFixtureAttributeAndIsAbstract() {
+			MockAttribute testAttribute = new MockAttribute("TestFixture");
+			MockClass mockClass = MockClass.CreateMockClassWithAttribute(testAttribute);
+			mockClass.Modifiers = mockClass.Modifiers | ModifierEnum.Abstract;
+			Assert.IsFalse(testFramework.IsTestClass(mockClass));
+		}
+		
 		[Test]
 		public void IsTestClassReturnsTrueHasClassHasTestFixtureAttribute()
 		{

src/AddIns/Analysis/UnitTesting/Test/Project/DuplicateMethodNameTestFixture.cs

@@ -34,7 +34,7 @@ namespace UnitTesting.Tests.Project
 			projectContent.Classes.Add(c);
 			
 			// Add first method.
-			MockMethod method = new MockMethod(c, "MyTest");
+			var method = new MockMethod(c, "MyTest");
 			method.Attributes.Add(new MockAttribute("Test"));
 			c.Methods.Add(method);
 			
@@ -46,8 +46,10 @@ namespace UnitTesting.Tests.Project
 			baseClass.Attributes.Add(new MockAttribute("TestFixture"));
 			projectContent.Classes.Add(baseClass);
 			c.AddBaseClass(baseClass);
-			baseClass.Methods.Add(method);
-			baseClass.Methods.Add(method);
+			var baseClassMethod = new MockMethod(baseClass, "MyTest");
+			baseClassMethod.Attributes.Add(new MockAttribute("Test"));
+			baseClass.Methods.Add(baseClassMethod);
+			baseClass.Methods.Add(baseClassMethod);
 			
 			// Create test class.
 			testClass = new TestClass(c, testFrameworks);
@@ -65,7 +67,7 @@ namespace UnitTesting.Tests.Project
 		[Test]
 		public void TestMethodName()
 		{
-			Assert.AreEqual("MyTestFixtureBase.MyTest", testClass.TestMembers[0].Name);
+			Assert.AreEqual("MyTest", testClass.TestMembers[0].Name);
 		}
 		
 		[Test]