How to assert if a private static void method ran with no errors in a unit test

Question

I am tryin to test a private static method like so:

public void myMethodTest()
        {
            MyClass target = new MyClass();
            PrivateType pt = new PrivateType(target.GetType());
            var x = pt.InvokeStatic("MyMethod");
          //Some type of Assert here
        }

The method also uses a private static variable within its class to check if its null, MyMethod is what im trying to test

private static HashSet<AnotherClass> fakeName{get;set;}

private static void MyMethod()
{
  if (null== fakeName)
  {
    fakeName = new HashSet<AnotherClass>();
  }
}

Thanks guys, if you need more clarification please let me know

In my Test if I do ,

Assert.IsNotNull(x);

the test fails, im just wondering if the method is actually been called , i followed this answer to run this test Stack answer

You don't directly test private members. You test the public behavior of the object. That public behavior would internally invoke private members. If the public behavior works, the object works. — David, Oct 16 '17 at 15:40
[Don't test internal or private code](http://blog.ploeh.dk/2015/09/22/unit-testing-internals). — Mark Seemann, Oct 16 '17 at 15:41
yeah I have read all this stuff, and i agree, but some times in life you are asked to do something even if you dont agree, so i have to test them lol — JohnChris, Oct 16 '17 at 15:42
If when you call `pt.InvokeStatic("MyMethod");` and there is an error the test will fail (and if there is not it will not). You dont need to assert anything. — Magnus, Oct 16 '17 at 15:44
@JohnChris: Well, what are you *asserting* with this test? What is this test meant to validate? — David, Oct 16 '17 at 15:44
@David... hmmm yeah good point.. its just that the method runs with no errors, but maybe thats pretty obvious already — JohnChris, Oct 16 '17 at 15:46
@JohnChris: Seems reasonable enough then. My arrange/act/assert structures often find the assert part to be nothing more than a comment indicating that the test passes if no exception is thrown. Some unit test frameworks also have ways to assert that explicitly, often as a method decoration. — David, Oct 16 '17 at 15:48
But if you know that it should throw exceptions under certain circumstances that is probably what you should test. — Magnus, Oct 16 '17 at 15:52

score 1 · Accepted Answer · answered Oct 17 '17 at 06:31

Using Typemock Isolator you can:

public void myMethodTest()
    {
        MyClass target = new MyClass();
        Isolate.Invoke.Method<MyClass>("MyMethod");
        Isolate.Verify.NonPublic.WasCalled(typeof(Dependency), "MyMethod");
    }

but it's commercial.

How to assert if a private static void method ran with no errors in a unit test

1 Answers1