Added operation tests

Author: michaelstaib

src/HotChocolate/Core/test/Types.Analyzers.Tests/OperationTests.cs

@@ -0,0 +1,25 @@
+namespace HotChocolate.Types;
+
+public class OperationTests
+{
+    [Fact]
+    public async Task Generate_Query_Resolvers()
+    {
+        await TestHelper.GetGeneratedSourceSnapshot(
+            """
+            using HotChocolate;
+            using HotChocolate.Types;
+
+            namespace TestNamespace;
+
+            [QueryType]
+            public static partial class Query
+            {
+                public static int GetTest(string arg)
+                {
+                    return arg.Length;
+                }
+            }
+            """).MatchMarkdownAsync();
+    }
+}