Diff btw "Invoke( lambda )" and directly calling a lambda when we use Google Mock EXPECT_CALL

Question

Since I learnt to use Google Test/Mock framework, I allways used the form to setup an expectation as following:

EXPECT_CALL( mock_obj, mock_method ).WillOnce( Invoke( []() { do_things; } ) );

Few days ago, I found that another form also can work as this:

EXPECT_CALL( mock_obj, mock_method ).WillOnce( []() { do_things; } );

My question is:

1. Is there any difference between those two forms?
2. When should I use one over another?

Thanks!

Answer 1

You have to use Invoke with some older versions of googletest (gtest/gmock) library - probably before 1.10.

Now it is mostly obsolete.

There are other Invoke* actions - see https://google.github.io/googletest/reference/actions.html#using-a-function-functor-or-lambda-as-an-action. Still any of these Invoke* are replaceable by custom lambdas - but why to do it if e.g. InvokeWithoutArgs(f) exists. I mean no point to replace InvokeWithoutArgs(f) with [](auto&&...) { f(); }