Update tests

src/Compilers/Core/CodeAnalysisTest/Diagnostics/OperationTests.cs

@@ -187,6 +187,7 @@ public void TestGetFlowGraphInvalidArgumentWithNullSemanticModel()
 
         private void TestGetFlowGraphInvalidArgumentCore(string argumentExceptionMessage, IOperation parent)
         {
+            bool exceptionThrown = false;
             try
             {
                 IBlockOperation block = new BlockStatement(
@@ -198,8 +199,12 @@ private void TestGetFlowGraphInvalidArgumentCore(string argumentExceptionMessage
             catch (ArgumentException ex)
             {
                 Assert.Equal(new ArgumentException(argumentExceptionMessage, "body").Message, ex.Message);
+                exceptionThrown = true;
             }
 
+            Assert.True(exceptionThrown);
+            exceptionThrown = false;
+
             try
             {
                 IFieldInitializerOperation initializer = new FieldInitializer(
@@ -212,8 +217,12 @@ private void TestGetFlowGraphInvalidArgumentCore(string argumentExceptionMessage
             catch (ArgumentException ex)
             {
                 Assert.Equal(new ArgumentException(argumentExceptionMessage, "initializer").Message, ex.Message);
+                exceptionThrown = true;
             }
 
+            Assert.True(exceptionThrown);
+            exceptionThrown = false;
+
             try
             {
                 IPropertyInitializerOperation initializer = new PropertyInitializer(
@@ -226,8 +235,12 @@ private void TestGetFlowGraphInvalidArgumentCore(string argumentExceptionMessage
             catch (ArgumentException ex)
             {
                 Assert.Equal(new ArgumentException(argumentExceptionMessage, "initializer").Message, ex.Message);
+                exceptionThrown = true;
             }
 
+            Assert.True(exceptionThrown);
+            exceptionThrown = false;
+
             try
             {
                 IParameterInitializerOperation initializer = new ParameterInitializer(
@@ -240,8 +253,12 @@ private void TestGetFlowGraphInvalidArgumentCore(string argumentExceptionMessage
             catch (ArgumentException ex)
             {
                 Assert.Equal(new ArgumentException(argumentExceptionMessage, "initializer").Message, ex.Message);
+                exceptionThrown = true;
             }
 
+            Assert.True(exceptionThrown);
+            exceptionThrown = false;
+
             try
             {
                 IConstructorBodyOperation constructorBody = new ConstructorBodyOperation(
@@ -256,8 +273,12 @@ private void TestGetFlowGraphInvalidArgumentCore(string argumentExceptionMessage
             catch (ArgumentException ex)
             {
                 Assert.Equal(new ArgumentException(argumentExceptionMessage, "constructorBody").Message, ex.Message);
+                exceptionThrown = true;
             }
 
+            Assert.True(exceptionThrown);
+            exceptionThrown = false;
+
             try
             {
                 IMethodBodyOperation methodBody = new MethodBodyOperation(
@@ -270,7 +291,11 @@ private void TestGetFlowGraphInvalidArgumentCore(string argumentExceptionMessage
             catch (ArgumentException ex)
             {
                 Assert.Equal(new ArgumentException(argumentExceptionMessage, "methodBody").Message, ex.Message);
+                exceptionThrown = true;
             }
+
+            Assert.True(exceptionThrown);
+            exceptionThrown = false;
         }
 
         [CompilerTrait(CompilerFeature.IOperation, CompilerFeature.Dataflow)]
@@ -293,6 +318,7 @@ void M(int x)
             var methodBodySyntax = tree.GetCompilationUnitRoot().DescendantNodes().OfType<BaseMethodDeclarationSyntax>().Last();
 
             // Verify ArgumentNullException
+            bool exceptionThrown = false;
             try
             {
                 _ = ControlFlowGraph.Create(node: null, model);
@@ -300,8 +326,12 @@ void M(int x)
             catch (ArgumentNullException ex)
             {
                 Assert.Equal(ex.Message, new ArgumentNullException("node").Message);
+                exceptionThrown = true;
             }
 
+            Assert.True(exceptionThrown);
+            exceptionThrown = false;
+
             try
             {
                 _ = ControlFlowGraph.Create(methodBodySyntax, semanticModel: null);
@@ -309,8 +339,12 @@ void M(int x)
             catch (ArgumentNullException ex)
             {
                 Assert.Equal(ex.Message, new ArgumentNullException("semanticModel").Message);
+                exceptionThrown = true;
             }
 
+            Assert.True(exceptionThrown);
+            exceptionThrown = false;
+
             // Verify argument exception on providing a syntax node in executable code which does not produce root operation.
             try
             {
@@ -320,8 +354,12 @@ void M(int x)
             catch (ArgumentException ex)
             {
                 Assert.Equal(ex.Message, new ArgumentException(CodeAnalysisResources.NotARootOperation, "operation").Message);
+                exceptionThrown = true;
             }
 
+            Assert.True(exceptionThrown);
+            exceptionThrown = false;
+
             // Verify null return for non-executable code syntax node, which does not produce an operation.
             var classDecl = tree.GetRoot().DescendantNodes().OfType<ClassDeclarationSyntax>().Single();
             Assert.Null(ControlFlowGraph.Create(classDecl, model));