FR: Reporter that prints the location of all expectations

[krlmlr]

Useful to locate test code that triggers a particular line of C++ or R code.

[hadley]

You're thinking of this when you get a segfault in the tests and want to quickly narrow down the code that causes it?

[krlmlr]

This, and also if I just set a breakpoint in C++ code and want to find the code that triggers it.

[krlmlr]

Awesome, thanks!

[krlmlr]

@hadley: Just used it for the first time, works as advertised. I've noticed two things:

• The reporter prints absolute paths on my system, is this intended?
• It would be helpful if it also printed the locations of each test_that() call (entry and exit)

[hadley]

Probably not - I'd be happy to review a PR.