Unit test that checks that Task-returning methods are postfixed 'Async"

NamingGuidelinesTest.cs

[TestMethod]
[TestCategory("Naming guidelines")]
public void TasksReturningMethodsArePostfixedAsync()
{
    var asm = typeof(SomeTypeInMyAssembly).Assembly;
    StringBuilder sb = new StringBuilder();
    foreach (var type in asm.GetExportedTypes())
    {
        foreach (var mi in type.GetMethods(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.NonPublic |
            System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.Static | 
            System.Reflection.BindingFlags.DeclaredOnly))
        {
            if (mi.IsPublic || mi.IsFamilyOrAssembly || mi.IsFamily) //public or protected internal or protected
            {
                if (mi.ReturnType == typeof(Task) ||
                    mi.ReturnType.IsGenericType && mi.ReturnType.Name.StartsWith(typeof(Task).FullName + "`"))
                {
                    if (!mi.Name.EndsWith("Async"))
                        sb.AppendFormat("{0}.{1}\n", type.FullName, mi.Name);
                }
            }
        }
    }
    Assert.IsTrue(sb.Length == 0,
        "Naming violation. The following Task-returning methods are not postfixed 'Async':\n" + sb.ToString());
}