A very small failing unit test to demonstrate how to use dlv at the command line for debugging tests.
From the command line, run:
$ dlv test
Then in a dlv prompt, run this...
(dlv) break TestFibonacci
To list the tests available to break on, run this ...
(dlv) funcs TestFi*
To break on the inner test, run this...
(dlv) break TestFibonacci.func1
You can always break on a line number...
(dlv) break ./fib_test.go:24