(Originally posted in #466. Moved here so I don't lose track of it once the source PR is merged.)

I was thinking of submitting a (separate) PR that adds an actual code modification to the e2e tests, so that we could get a look at the diff coverage reporting as well. That's the part, if anything, that I think might need adjusting with branch coverage enabled.

(I figured I'd drop the test-ed function to just contain

def f(a="", b="", c="", d=""):
      elements = []
      if a:
          elements.append(a)
      if b:
          elements.append(b)
      """__ADD_CODE_HERE__"""
      return "-".join(elements)

...And then have the e2e test function insert the if c: and if d: blocks. (Or maybe even if c: ... elif d: which might make for better branch coverage testing.)