Macro __result_of 

macro_rules! __result_of {
    ($function: expr, $matcher: expr) => { ... };
}

Matches a value where the result of callable applied to the value matches the inner matcher.

The callable will be called twice, so make sure it is pure.

use googletest::prelude::*;
fn should_pass() -> googletest::Result<()> {
   verify_that!(100, result_of!(|value| value + 1, eq(101)))?; // Passes
   Ok(())
}

fn should_fail() -> googletest::Result<()> {
   verify_that!(100, result_of!(|value| value * 2, eq(100)))?; // Fails
   Ok(())
}
should_pass().unwrap();
should_fail().unwrap_err();